Air quality remains ‘satisfactory’ as Delhi warms up to economic activity
An official said an increase in the number of vehicles on roads may degrade air quality. But good wind speed expected over the next two days is likely to mitigate the detrimental effects.Updated: May 05, 2020 07:40 IST
Pollution levels in Delhi remained in the ‘satisfactory’ zone on Monday even as many government and private offices opened with a third of their staff on the first day of the two-week exit from the lockdown, because of which there was increased activity and traffic presence in the city.
Experts said it will take some time to analyse the impact of resumption of activity on the pollution levels. High wind speed and frequent spells of rain will, however, help keep pollution in check for the rest of the week.
According to Central Pollution Control Board’s (CPCB) bulletin released at 9pm, the average air quality index (AQI) on Monday was 90 ( in the ‘satisfactory’ zone).
At 93, the AQI on Sunday was also in the ‘satisfactory’ zone.
The last time Delhi experienced ‘satisfactory’ air quality was on April 27 when the index was recorded at 89.
“Pollution levels in the city during the lockdown period have mostly fluctuated between ‘moderate’ and ‘satisfactory’ levels, mainly because of no traffic movement or activity, apart from the good weather and frequent rainfall. Since it was just the first day of relaxations coming into effect, any impact on overall pollution levels will only be reflected late night or tomorrow (Tuesday) morning,” a senior CPCB official, who did not wish to be named, said.
The official said an increase in the number of vehicles on roads may degrade air quality. But good wind speed expected over the next two days is likely to mitigate the detrimental effects.
According to scientists at India Meteorological Department (IMD), on Sunday evening the wind speed went up to 58 kmph, the highest for Delhi this summer. The high wind speed and rainfall helped push the air quality from ‘moderate’ to ‘satisfactory’.
“The air quality is likely to improve further on Tuesday, with the wind speed expected to go up to 40-50 kmph between Monday night and Tuesday morning. Delhi has had six western disturbances in April, as against the usual three to four, resulting in frequent thunderstorms and rainfall. We are expecting another western disturbance to hit northwestern India between May 10 and May 12 and it will result in rain and gusty winds,” Kuldeep Srivastava, head, IMD’s regional weather forecasting centre, said.
According to experts, since Monday was just the first day of more private vehicles plying on roads and economic activity slowly starting to pick up, the impact of the emissions will take a while to reflect in the pollution levels.
“So far we don’t know the quantum of the vehicles plying on the roads. Any significant increase in the traffic will impact NOx levels and there will be some impact on PM 2.5 levels as well. But we will need to analyse data for at least a week to establish a trend,” Anumita Roychowdhury, executive director, research and advocacy, Centre for Science and Environment (CSE), said.
Roychowdhury said that so far, the prominent pollutant in the air was PM 10 (mainly generated from dust) because intrusion of dust is higher during summers.
According to the System of Air Quality and Weather Forecasting and Research (SAFAR), the union government’s air quality monitoring and forecasting wing, air quality may improve to ‘good’ level by Tuesday. “Rainfall has resulted in washing out of pollutants and air quality is expected to improve over the next two days,” its bulletin said.