Despite 90 per cent vehicles remaining off the roads in India during the summer months of 2020 due to the Covid-19 pandemic and the subsequent lockdown, the expected ‘near-zero’ pollution level was not achieved in the megacities of Delhi and Mumbai, once again highlighting the need for long-term and effective measures to curb pollution.
A joint study, undertaken by scientists from the Pune-based Indian Institute of Tropical Meteorology (IITM) and Utkal University, Bhubaneshwar, has concluded that Carbon Monoxide (CO) levels during the lockdown in these cities had dropped compared to normal days. However, this could not touch the lowest or ‘near-zero’ pollution level, due to continuing contributions made by CO fumes emitted from household cooking.
Experts say that after the transport sector, household cooking is the second major contributor to CO gas in the atmosphere. In Delhi, the share of CO emitted from household cooking is 4 per cent (1.38 Gigagram/month), while it is 31 per cent (13.67 Gigagram/month) in Mumbai, according to the study published in the Environmental Pollution journal on Tuesday.
CO is one of the remnant gaseous matter produced as a result of incomplete fuel combustion in vehicles, oil, coal, natural gas and even wood. Prolonged exposure to CO can cause stomach ache, tiredness and dizziness. Its fumes are harmful for pregnant women and the elderly, and also those with compromised respiratory conditions.
During the initial phases of the lockdown (March to May 2020), CO concentration fell by 86 and 62 per cent in Delhi and Mumbai, respectively, as per the SAFAR data used for the research.
As opposed to 34.85 Gigagram/month, Delhi’s CO concentration fell to 4.74 Gigagram/month. In Mumbai, the decline was from 44.23 Gigagram/month to 16.75 Gigagram/month, said the researchers.
Even though the CO levels in Mumbai were higher than Delhi between March to May last year, scientists found that its prevalence in the atmosphere over the commercial capital was for a shorter duration.
“The constant sea breeze over Mumbai could dilute the effects of CO, whereas over Delhi, it prevailed for a long time,” highlighted the study.