An analysis of levels of various pollutants on Diwali day since 2010 reveals a disturbing trend. Levels of some pollutants, including sulphur dioxide (SO2) and nitrogen dioxide (NO2), seem to be on the rise.

The levels of particulate matter (PM) 2.5 (particles smaller than 2.5 micrometres), which have serious health implications as these tend to get lodged in the lung and can even enter the bloodstream, have been seven to eight times higher than the standard level for several years.

PM 2.5 is associated with a number of health impacts such as asthma, bronchitis, chronic respiratory symptoms including, shortness of breath and painful breathing, and premature deaths. High SO2 levels are also linked with inflammation of airways and severe breathing difficulty.

Meanwhile, the Delhi Pollution Control Committee (DPCC) on Friday announced that it had formed seven teams to assist DCs and visit various areas to check noise levels on Diwali. It asked the Delhi Police to ensure that the total number of firecracker licences issued this year should not exceed the last year's figure.

List of licences granted to be displayed on the official website of licensing unit of the Delhi Police, a copy of which is to be given to the DPCC.

Sub-divisional magistrates have been asked to organize meetings with RWAs to sensitize them about of Supreme Court directions regarding complete ban on bursting of sound emitting firecrackers between 10pm and 6am.

As far as air pollution is concerned, Anand Vihar seems to be the worst affected. PM 10 (coarse particles) levels have been 10 to 13 times higher than the standard level in 2012 and 2013,

PM 2.5 levels have been about seven to eight times the standard. Experts say heavy traffic in Anand Vihar and vehicles from Ghaziabad may be adding to the Diwali emissions. "We have noticed that even on regular days, air pollution levels are on the higher side in Anand Vihar, Civil Lines and IGI Airport. In Anand Vihar, the interstate traffic may be causing levels to go up. As for high SO2 levels, they may be from imported crackers that seem to have high sulphur content," said Anumita Roy Chowdhury, head of clean air programme at the Centre for Science and Environment (CSE).

M P George, scientist at the DPCC air lab, said Anand Vihar's high particulate matter levels could also be linked to the industries near the Delhi border.

Delhi Pollution Control Committee had tested firecracker samples recently and found most of them to be flouting the Explosives Rules, 2008, as their manufacturers did not mention the chemical composition on the packages. This means that there is no monitoring of the heavy metals that are also emitted from crackers.

"You will notice that a lot of colour crackers are being used now. So they are not just noisy and polluting, they may be causing toxic pollution due to presence of heavy metals. We are not even aware of what health impacts these coloured and imported crackers may be causing," added Roy Chowdhury.