Starting on 21 February, the Trump administration is extending its so-called “travel ban” to cover six new countries: Nigeria, Eritrea, Tanzania, Sudan, Kyrgyzstan and Myanmar.

The expansion restricts hundreds of millions more people from immigrating to the US or obtaining certain kinds of visas.

Here’s a guide to what the expansion means for the countries and people affected – and some of its wider implications.

What does the overall ban do?

The travel ban in place since 2018 restricts the issuance of immigrant and non-immigrant visas to applicants from Iran, Libya, Somalia, Syria and Yemen, along with Venezuela and North Korea.

Sudan – now on the extended list – was originally included and then removed. Chad was briefly on the list too, but was removed after it improved security measures.

The ban went through three iterations before being upheld by the Supreme Court in June 2018. Justices dissenting from the judgment said it “erodes the foundational principles of religious tolerance that the court elsewhere has so emphatically protected”.

New York City bodegas strike to protest Trump's travel ban Show all 27 1 /27 New York City bodegas strike to protest Trump's travel ban New York City bodegas strike to protest Trump's travel ban Ethnic Yemenis and supporters protest against President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban Men pray during a protest by ethnic Yemenis and supporters over President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban Ethnic Yemenis and supporters protest against President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban Men pray during a protest by ethnic Yemenis and supporters over President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People gather for evening prayer at a rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner places a sign on the gate of his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner places a sign on the gate of his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban NEW YORK, NY - FEBRUARY 02: Yemeni business owner Musa closes the gate to his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner closes the gate to his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty

What countries does the extended ban include, and why?

The Department of Homeland Security (DHS) has now added Nigeria, Eritrea, Tanzania, Sudan, Kyrgyzstan and Myanmar to its list of travel-restricted countries.

In its original announcement, the department said the move is “the product of a comprehensive and systematic global assessment conducted by the Department of Homeland Security and the interagency”.

Explaining the basis for the new list, DHS said: “These restrictions are tailored to country-specific deficiencies, as well as travel-related risk to the homeland.

“These restrictions do not reflect animus or bias against any particular country, region, ethnicity, race, or religion.”

That last caveat is a defence against accusations that the overall ban deliberately targets Muslims – accusations that in turn stem from a campaign promise Trump made in 2015, when he called for “a total and complete shutdown of Muslims entering the United States until our country’s representatives can figure out what the hell is going on”.

New expansion restricts hundreds of millions more people from immigrating to the US or obtaining certain kinds of visas (Statista)

What’s different from the original ban?

The original ban does not apply evenly to all seven countries. The inclusion of North Korea is all but meaningless since that country’s government heavily restricts travel to the US anyway, while the ban on Venezuela only extends to a small number of people from the country’s power elite.

The other five countries, however, are Muslim-majority – and almost all their citizens are effectively barred from travelling to the US except under certain circumstances. And while people from the affected countries can apply for “waivers” from the policy’s restrictions, they still need to apply for visas even if they are exempted.

The new list’s scope, however, is more limited.

On Eritrea, Kyrgyzstan, Myanmar and Nigeria, the administration is restricting the issuance of immigrant visas. Its rationale is that these countries are “deficient” in sharing information about terrorists and criminals and have failed or refused to improve their security measures.

That means information that a visa applicant is a “threat” will probably not be available at the time they apply. And because “individuals who have entered the US on immigrant visas are challenging to remove”, DHS takes the view that restricting these visas is the only safe cause of action.

Sudan and Tanzania, meanwhile, have apparently performed better against the administration’s security criteria. On that basis, the administration has decided to impose restrictions on Diversity Visas – also known as the “green card lottery” – which DHS describes as “a less serious sanction” given “the significantly fewer number of aliens affected”.

Who is and isn’t affected?

The DHS’s announcement made clear that the extended ban’s remit is limited only to those who apply for the visas in question. People abroad who already have a valid visa but have not yet entered the US can still come to the US, and legally documented residents already in the US can still reside there.

Many other visitors, said the department, will also be unaffected: “Family members can still visit their loved ones, businesses can still employ qualified candidates, and other visits can take place on a temporary basis with a non-immigrant visa.”

The statement also specified that travellers already en route to the US when the ban came into force would not be affected.

How can countries get off the list?

DHS stressed that it’s possible for a country to get the ban lifted: “The restrictions imposed by the president reflect our greater confidence that these countries can make meaningful improvements in a reasonable period of time. If the restricted countries do, the president may remove travel restrictions at any time.”

There is a precedent for this. Chad was added to the original ban’s list in 2017, but was removed the following spring after apparently improving its information-sharing practices and making its passports more secure.

How has the ban been received?

The expansion of the ban has been met with outrage from many quarters. Democratic presidential candidate Bernie Sanders tweeted that: “My first executive orders will be to reverse every single thing President Trump has done to demonise and harm immigrants, including his racist and disgusting Muslim ban”.

The House of Representatives Judiciary Committee, meanwhile, passed the “No Ban Act”, which would repeal the ban altogether and limit the president’s ability to impose future restrictions based on religion. Given the partisan makeup of Congress, it is not expected to make it into law.