The Indian government launched a new air quality index on Monday, under intense pressure to act after the World Health Organization declared New Delhi the world's most polluted capital.

Environment Minister Prakash Javadekar said the government would publish air quality data for 10 cities, amid growing public concern over the impact of air pollution on the health of the country's 1.2 billion people.

"The Air Quality Index may prove to be a major impetus to improving air quality in urban areas, as it will improve public awareness in cities to take steps for air pollution mitigation," Javadekar said as he launched the index at a conference on the environment.