Status of air pollution during winter of 2015-16 and the impact of odd-even car rationing scheme on air quality

January 21, 2016

1. Overall pollution level this winter is higher than last winter. This demands emergency action

This winter has witnessed extremely high level of pollution. Typical winter conditions -- cold temperature, lower mixing height of air, calm and no-wind conditions trap air and pollution. As a result, pollution builds up very quickly and peaks. This is why winter months require tougher emergency action to reduce pollution. Weather is an important constraint in pollution management.  

The winter months of November and December 2015 show higher number of days in severe category-four times the safe standard – which is the worst category according to the National Air Quality Index. November 2015 had 73% cent of days in severe category against 53% in November, 2014. December 2015 has 67% of days in severe category as against 65% in December 2014. December 2014 at least had 3% of days in good and satisfactory category but December 2015 has none. There has not been a single good air quality day this winter. On several consecutive days, the PM2.5 levels have remained in the worst category according to the national air quality index.

The odd and even programme has been implemented as an emergency action to arrest the high emergency peak when the overall pollution levels have gone 5 to 6 times higher than the standards. This is needed to protect public health in a city where every third child has impaired lungs.