However, pockets like Chembur recorded the worst AQI of 246, followed by 223 at Bandra Kurla Complex (BKC), 213 at Shivaji Nagar (Mankhurd), 212 at Ghatkopar and 210 at Byculla.

AQI readings between 0-50 are regarded as good, 51-100 is regarded as satisfactory, 101-200 is regarded as moderate, 201-300 is regarded as poor, 301-400 is regarded as very poor and above 400 is considered to be severe

Last month, to keep a check on the growing menace of air pollution, the BMC had implemented Graded Response Action Plan (GRAP) regulations in the city announcing a stay on construction works in areas that would record AQI reading above 200. The BMC had stopped Construction works in Byculla, Ghatkopar and Borivali areas last week that saw spikes in local pollution levels.

On Sunday areas like BKC, Ghatkopar, Chembur and Mankhurd continued to record poor AQI.

A senior civic official from Ghatkopar’s N ward told The Indian Express, “At present sewage operation works are underway in many areas which record digging and trenching works. This has led to a spike in the local AQI. Even though we haven’t stopped this work entirely, activities like water sprinkling and fogging are being carried out to keep the situation under check”.

Another civic official from Byculla’s E ward said that all private construction works have already been stopped in this area.

“The only work that is undergoing Byculla right now is the road concretisation project. Since we have a strict deadline, this project is being given relaxation and besides this all private works have been stopped,” the official added.

A senior official from BMC’s environment department said that after the AQI improved on January 2 onwards, construction works in Mumbai were given a relaxation. However, the authorities will monitor the situation for two days, following which a call will be taken on whether restrictions are to be imposed again.

“We will have to continuously monitor the readings for 48-hours at least to check if the AQI stays under the poor category. Because we are taking real time action on ground round the clock and if despite the effort the situation doesn’t improve then only action would be taken. Besides man made factors, current climatic conditions are also affecting the overall AQI of Mumbai,” said the official.

Gufran Beig, chair-professor of National Institute of Advanced Sciences (NIAS) said that besides the current dip in temperature. Dust storms from the Middle East are also affecting Mumbai’s overall AQI conditions.

“Dust storms have originated in the borders of Afghanistan, Iran and these dust particles have entered the region around the Arabian sea – eventually affecting its coastal region including Mumbai. Satellite images have also shown dust intrusion entering the sea from Pakistan, Afghanistan towards Mumbai,” Beig told The Indian Express.

“As a result, Mumbai’s air has become heavy due to the presence of pollutants that are leading to formation of haze, which is reducing visibility. Probably, the layer of haze that has been formed is sitting quite higher from the ground where the monitoring stations are located, as a result the actual readings could not be read in the system,” Beig added.

Mumbai’s minimum temperature rises

On Sunday, Mumbai’s minimum temperature saw a rise by 3 degrees in the past 24 hours, as the India Meteorology Department’s (IMD) Santacruz observatory recorded a minimum temperature of 19 degrees – which was 2.2 degrees above normal levels.

Earlier on January 4 (Saturday) the minimum temperature recorded was 16.2 degrees – a degree below normal levels. The bureau in its weekly forecast maintained that in the next one week both minimum and maximum temperatures may record a further dip.