India unveiled a National Air Quality Index Monday to keep track of pollution levels in 10 of its cities.
Prime Minister Narendra Modi announced the new measure at a conference of state environment ministers in New Delhi.
Mr. Modi said India, with its strong tradition of protecting the environment, has one of the world's lowest pollution levels.
That claim was disputed by a World Health Organization report last year that said New Delhi has the world's dirtiest air.
The new index will inform Indian citizens whether the air quality for the day is healthy, poor, harmful or hazardous.