New Delhi: Germany’s Chancellor Angela Merkel urged greater efforts to clean up New Delhi’s toxic air as she pledged one billion euros to help Indian cities switch to green transport.

Merkel became a rare foreign leader to speak out on India’s smog crisis after being exposed to the capital’s air on Friday, when authorities said the pollution had reached “emergency” levels.

Schools were ordered closed until Tuesday and all construction halted, while Delhi authorities started distributing millions of anti-pollution masks to children.

The same day, Merkel went on a ceremonial parade in the city with Prime Minister Narendra Modi on Friday as the smog intensified.

Neither leader wore masks despite authorities telling residents to stay indoors to avoid the haze.

Merkel said that Germany would spend one billion euros on “green” urban transport projects in India over the next five years, including 200 million euros to replace diesel buses in Tamil Nadu state.

“These diesel buses are to be replaced by electric buses and anyone who saw the pollution in Delhi yesterday would find very good arguments for replacing even more of these buses,” Merkel said in the widely reported speech.

Much of the new peak in the most dangerous PM 2.5 pollutants - particulates smaller than 2.5 microns that get into the lungs and bloodstream - has been blamed on fires lit by farmers to burn off wheat crop residues outside of the capital.

Higher winds improved air quality on Saturday but pollution remained “severe”, according to government monitors.

Delhi has faced a mounting pollution crisis over the past decade.

Fourteen Indian cities including the capital are among the world’s top 15 most polluted cities, according to the United Nations.

According to one study, smog kills a million Indians prematurely every year.