Delhi's deadly smog was visible during Angela Merkel's welcome at Rashtrapati Bhavan.

Highlights Delhi's smog was visible during Angela Merkel's welcome ceremony

She pitched speeding up projects such as introduction of electric buses

She said Germany will spend one billion euros on green projects in India

German Chancellor Angela Merkel on Saturday made a pitch for speeding up several environment friendly projects such as the introduction of electric buses to replace diesel ones used for public transport in urban centres, expressing concern at the alarming pollution levels in New Delhi.

"We will also earmark 200 million euros to reform bus sector in Tamil Nadu. Whoever has looked at pollution in Delhi yesterday would find very good arguments to replacing diesel buses with electric buses," Ms Merkel was quoted as saying by news agency ANI at a business meeting in Delhi.

She said Germany will spend one billion euros or $1.12 billion in the next five years on green urban mobility projects conceived under the new German-Indian partnership. German funds will be used to finance several environment-friendly projects including electric buses.

The announcement comes at a time when pollution made the air so toxic in New Delhi that officials were forced to declare a public health emergency.

Visuals of Ms Merkel's ceremonial welcome at the Rashtrapati Bhavan, the presidential palace, showed the visible effects of smog - though both Prime Minister Narendra Modi and the German leader were not seen wearing masks.

A thick haze has hung over the capital this week caused by plumes of toxic smoke from farm waste being burnt in neighbouring states.

Delhi Chief Minister Arvind Kejriwal ordered schools shut till Tuesday to protect children and banned all construction activity till next week.

An index measuring the level of a deadly air pollutant hit 484 on a scale of 500 on Friday, the government's Central Pollution Control Board said, the worst this year.

The index measures the level of PM 2.5, tiny particulate matter that goes deep into the lungs. Anything above 400 poses a risk for people with respiratory illnesses and can also affect even those with healthy lungs.

The toxic air has also left several Bangladeshi cricket players with sore throats and itchy eyes ahead of their Twenty20 match against India on Sunday.