Pollution levels in Delhi, which remained choked with toxic air on Monday, will start improving only on Wednesday.
According to System of Air Quality and Weather Forecasting and Research (SAFAR), Delhi’s air will remain in the ‘severe’ range on Tuesday and will improve — to ‘very poor’ — on Wednesday with an increase in wind speed.
A mix of Diwali crackers, high humidity, low temperature and low wind speed in Delhi meant that pollutants got accumulated in the air. A relatively high wind speed dispersed pollutants, but it has been in the range of 0.3 metres per second and 2 metres per second since Saturday. Usually, it is between 2 metres per second and 4 metres per second in the capital.
According to a statement issued by the Delhi government, the level of pollutants spiked on Diwali. “The major changes (in air quality) were observed after 7 pm, when fireworks started. Ambient air quality in Delhi was already saturated with pollutants accumulated due to trans-state movement of pollutants. The cumulative effect of existing pollution load and pollutants’ release due to fireworks, as well as adverse meteorological conditions, led to the present situation,” the statement read.
On Monday, all stations across the city saw air quality drop down to ‘severe’ levels. The National Air Quality Index reported pollution levels at 500, the highest it can go at all seven stations that measure particulate matter (PM). Any reading between 400 and 500 on the National Air Quality Index means the air is severely polluted.
The primary pollutants at all stations were particulate matter, which is caused by burning, vehicular emissions and industrial pollutants.
The US embassy’s monitoring station showed the air quality reading at a high 999 between Sunday evening and Monday evening.
Air pollution: Data showing particulate matter levels in different cities across India. (Source: http://aqicn.org/)
According to the Delhi Pollution Control Committee (DPCC) stations, the PM .5 levels at Punjabi Bagh reached a high of 678 micrograms per cubic metre at 2 am on Monday. By 5.30 pm, it had dropped to 124 micrograms per cubic metre but the air quality will take time to improve. The PM 10 level rose to 1,560 micrograms per cubic metre at 2 am.
At R K Puram, PM 2.5 was 748 micrograms per cubic metre while the PM 10 levels were 1,400 micrograms per cubic metre at 2 am. The standard for PM 2.5 and PM 10 is 60 and 100 micrograms per cubic metre respectively. “Emissions caused by crackers added to already high PM 2.5 levels in the city. Levels were higher than last year… due to outside contributions from agricultural burning. Lower wind speed and shallow inversion layer can lead to extremely high pollutant concentrations in winters. A regional, multi-sectoral air quality management plan is required for NCR,” said Sumit Sharma, Fellow, The Energy and Resources Institute.
At a meeting headed by Environment Minister Imrain Hussain, experts attributed high levels of pollution to adverse weather conditions and agricultural burning in neighbouring states. The Ministry of Environment, Forest and Climate Change also reviewed the ambient air quality status of Delhi.
Delhi is the eleventh most polluted city in the world, according to the World Health Organisation. The city has not seen a single good air-quality day since September.