Google has published charts showing how the coronavirus has brought hard-hit Italy to a standstill, led to runs on grocery stores around the world and prompted a stark drop in going out between Mardi Gras and St. Patrick's Day.

The analysis of location data from billions of Google users' phones is the largest public data set available to help health authorities assess if people are abiding with shelter-in-place and similar orders issued across the world to rein in the virus.

The company released reports for 131 countries — including Canada — with charts that compare traffic from Feb. 16 to March 29 to retail and recreational venues, train and bus stations, grocery stores and workplaces with a five-week period earlier this year.

Google said it published the reports to avoid any confusion about what it was providing to authorities, given the global debate that has emerged about balancing privacy-invasive location tracking with the need to prevent further outbreaks.

The data often correlated with the severity of outbreaks and the harshness and breadth of orders imposed by governments.

Italy, Spain see major drops

Italy and Spain, two of the hardest-hit countries, both saw visits to retail and recreation locations such as restaurants and movie theatres plunge 94 per cent. The United Kingdom, France and Philippines had declines of more than 80 per cent while India, which went into a sudden 21-day lockdown on March 25, was also notable at 77 per cent.

Canada has seen drops that are less steep, though still significant. Retail and recreation Canada-wide has gone down by 59 per cent, while Quebec — the hardest-hit province, with more than 5,500 cases — has seen the greatest reduction, at 70 per cent. In New Brunswick, the data shows an increase in visits to parks, while Nova Scotia has a reduction of only five per cent.

Google's mobility results for Canada, which show how movement has changed among Canadians during the COVID-19 pandemic. On average, trips to all types of sites have dropped, including a 70 per cent reduction to retail and recreation locations in Quebec. (Google)

In the United States, where state responses have varied greatly, and in Australia, where good weather initially prompted many people to go the beach before social distancing measures were ratcheted up, the drop in visits to retail and recreation sites were less steep, at under 50 per cent.

In contrast, in Japan and Sweden, where authorities have not imposed harsh restrictions, visits fell by roughly only a quarter. In South Korea, which has successfully contained a large outbreak through aggressive testing and contact tracing, the decline was just 19 per cent.

Challenges remain in keeping people apart

The data also underscore some challenges authorities have faced in keeping people apart. Grocery store visits surged in Singapore, the U.K. and elsewhere as travel restrictions were set to go into place. Visits to parks spiked in March in some San Francisco Bay Area counties under lockdown in California, forcing them to later put the sites off-limits.

The data also underscores how the mood of people around the world has shifted. In New Orleans, during its annual Mardi Gras celebrations Feb.16-25, which has with hindsight been criticized for helping spread the virus, there were off-the-chart increases in traffic to transit stations, parks and businesses.

But three weeks later in Dublin, the heart of St. Patrick's holiday celebrations, traffic was down at retail and recreational venues as the country ordered big events cancelled.

A man wearing a shamrock suit walks along the normally bustling St. Patrick's Day parade route on O'Connell Street in Dublin, March 17, 2020. The event that draws thousands of visitors to the island from across the world was cancelled by the Irish government in their response to the Covid-19 virus pandemic. (Charles McQuillan/Getty Images)

Within countries, there were wide gaps in behaviour by region. California, which was the first in the U.S. with a statewide lockdown, cut visits to retail and recreation locations by half. In New York state, the slide in such visits was gradual as officials waited to impose strict curbs, but they eventually fell 62 per cent. By contrast, Arkansas, one of the few states without a sweeping lockdown, had the smallest decline, at 29 per cent.

The coronavirus has infected more than one million people globally, and COVID-19, the respiratory illness it causes, has killed 53,000, according to a tally by Johns Hopkins University.

There were no reports for China and Iran, where Google services are blocked.

Balancing privacy

Data in Google's reports come from users who enabled Google's "Location History" feature on their devices. The company said it adopted technical measures to ensure that no individual could be identified through the new reports.

"These reports have been developed to be helpful while adhering to our stringent privacy protocols and policies," Dr. Karen DeSalvo, chief health officer for Google Health and Jen Fitzpatrick, senior vice president for Google Geo, wrote in a blog post.

China, Singapore, South Korea and other countries have asked residents to use apps and other technology to track their compliance with quarantines, but privacy activists argue such measures can compromise individual liberties.

Infectious disease specialists have said analyzing travel across groups by age, income and other demographics could help shape public service announcements.

Google, which infers demographics from users' internet use as well as some data given when signing up to Google services, said it was not reporting demographic information. The company said, though, it was open to including additional information and countries in follow-up reports.

Google said consultations with officials in the U.S. and the World Health Organization helped inform the data shared.

The company declined to comment on whether it has received any legal requests to share more detailed data to help with efforts to tackle the pandemic.

Facebook, which like Google has billions of users, has shared location data with non-governmental researchers that are producing similar reports for authorities in several countries. But the social media giant has not published any findings.