Delhi's air is among the most polluted in 230 Asian cities, a new survey has found.
An analysis of air quality by Clean Air Initiative for Asian Cities has found that particulate matter (PM) of Delhi in 2008 had ranged between 201 and 250 micro grams in a cubic meter of air (ug/m3), more than double the national standard for PM 10.
High particulate matter causes breathing problems and can stir asthma attacks. The PM level in Delhi is on rise since 2006 after witnessing a fall for almost five years after introduction of Compressed Natural Gas for public transport in the Capital.
Anumita Roy Chowdhury, associate director of Centre for Science and Environment, said the rising levels of particulate matter were an area of concern.
"Despite Metro trains, the phenomenal increase in number of vehicles in Delhi leading to congestion is a reason for air quality turning bad," she said. The survey found that while air quality in most Asian cities had improved by imposing restrictions on use of personal transport and providing better public transport, the same has not happened in major Indian cities.
Besides Delhi, other northern Indian cities such as Kanpur, Lucknow and Ludhiana were categorised as bad on the air pollution scoreboard, developed by Asian Development Bank.
Five cities that got the top ranking were Bangkok, Hanoi, Jakarta, Jinan and Manila. The other three cities — Colombo, Hangzhou, and Kathmandu —scored "moderate".
While none of the surveyed cities received a "minimal" score, neither did any of them score "excellent", showing there is ample room for improvement, the survey released at a conference in Singapore said.
"Rather than ranking cities based on air pollution alone, it is important to look at existing capacity, policies and measures as these are better indicators for their future levels of air pollution," said Sophie Punte, Executive Director of the CAI-Asia Centre.