NEW DELHI: Delhi’s pollution levels between March and May this year were almost the same as the pollution levels during the same period in 2019, despite the city being in full lockdown for over a month in 2021, data analysed by a climate communications initiative, Climate Trends, reveals.
Track the pollution level in your cityWhile the levels were much lower in 2020, when there was also a full lockdown, the average PM2.5 levels this year were 95 micrograms per cubic metre — almost the same as 95.7ug/m3 recorded in 2019.
The analysis also shows despite lockdowns, the pollution levels in both Delhi and Lucknow were above permissible limits, highlighting high background emissions.
The other cities analysed included Mumbai where the average PM2.5 concentration has only increased year on year during March, April and May from 2019 to 2021.
Kolkata was the only city to show improvement in the air quality during this period.
Researchers compared Central Pollution Control Board (CPCB)’s air quality data for Delhi, Lucknow, Mumbai and Kolkata over March, April and May in 2019 when there was no lockdown, and 2020 and 2021, when there was complete lockdown.
Mumbai’s average concentration of PM2.5 between March and May in 2019 was 21.6ug/m3 that increased to 31.3 in 2020 and then to 40.3 in 2021.
The safe limit for PM2.5 as prescribed by CPCB is 60ug/m3.
“Mumbai being a coastal city has a mixed effect of local meteorology and prevalent conditions of large-scale motions, including that of cyclones.
While cyclones such as Tauktae act as a washout/cleaning effect on the atmosphere, slow wind conditions, favourable conditions of long transport of particulate matters from neighbouring states act as accumulation, suggesting marginal increase of pollutants,” said professor S K Dhaka of Rajdhani College at Delhi University.
Delhi’s average PM2.5 concentration for the three months dipped from 95.6ug/m3 in 2019 to 69 in 2020, but was back to 95ug/m3 in 2021.
Kolkata’s PM2.5 concentration swayed from 41.8ug/m3 in 2019 to 27.9 in 2020 and 37.3 in 2021.
While there was a complete lockdown in 2020, the 2021 lockdown saw high movement of people due to the assembly elections.
G C Kisku, chief scientist of environmental toxicology at CSIR-Indian Institute of Toxicology Research, said, “The partial/complete lockdowns lowered vehicular movement and subsequently led to reduced consumption of fossil fuels.
Closure of industrial establishments during lockdown periods also added to it.
But the levels are still relatively higher this year.” The good thing is, he added, there has been a decreasing trend in PM10 levels from 2017, though the observed levels of PM2.5, PM10, SO2 and NO2 at all locations this year were relatively higher compared to the previous year.
CSIR also recently released a report on the assessment of ambient air quality of Lucknow that showed that the mean levels of PM10 (127.1g/m3) and PM2.5 (64.5g/m3) at all monitoring locations in residential, commercial and industrial areas from April-May 2021 were higher than permissible limits.
Any relief from lockdown-resultant pollution levels cannot be rejoiced, feel experts.
“Lockdown-related reduction in air pollution is neither consistent nor uniform.
The contribution of anthropogenic activities do not totally explain the high pollution level.
Thus, we should stay alert about the continuing health hazards of high pollutant levels, especially in metropolitan cities,” said Arun Sharma, president of Society for Indoor Environment.