Mumbai weather updates: Air quality deteriorates, city struggles to breathe

The Mumbai skyline is obscured by a blanket of dense haze. File pic/Kirti Surve Parade

Mumbai continued to experience poor air quality across the city post-Diwali. Navy Nagar in Colaba, Kandivli West, Sewri, Malad West, Bandra Kurla Complex and Kherwadi-Bandra recorded the worst AQI levels during the festival. While the city's overall AQI has slightly improved, many areas still face poor to very poor air quality.

According to the Central Pollution Control Board's SAMEER app, Mumbai's AQI on Sunday was 157 (moderate), down from Saturday's 208 (poor) - the city's highest AQI in 2024 so far. Navy Nagar, Colaba reported the city's worst reading on Sunday, reaching an AQI of 317 (recorded by IITM) in the ‘very poor' range. Kandivli West (BMC) recorded 244, Sewri (BMC) 233, Malad West (BMC) 232, Bandra Kurla Complex (MPCB) 211 and Kherwadi, Bandra 208.

For reference, the AQI scale rates air quality as ‘good' between 0-50, ‘satisfactory' from 51-100, ‘moderate' from 101-200, ‘poor' between 201-300, ‘very poor' from 301-400, and anything above 400 as ‘severe.'

The post-Diwali pollution underscores the impact of festival emissions on air quality, with some neighbourhoods faring worse than others. The situation highlights the need for ongoing air quality management, especially after high-emission events.

Feeling the heat

Though November is typically a winter month, Mumbaikars are experiencing an unexpected heatwave, with temperatures above 34°C in the first days. This early November warmth isn't unprecedented; past records show similar peaks, like 37°C on November 4, 2014, and 37.4°C on November 4, 2018. This year, November 2 and Novemvber 3 both reached 36.5°C, making Mumbai hottest in Maharashtra, even surpassing warmer regions like Akola and Jalgaon. Meteorologists expect temperatures to stay around 34°C to 35°C for a few more days, with cooler nights setting in later.

Expert Speak

Climatologist Rajesh Kapadia from Vagaries of the Weather, a private forecasting blog, explained the conditions, saying, "These high temperatures often occur following the withdrawal of the monsoon. The wind pattern shifts from westerly to easterly, bringing in hot, dry inland winds from the east. This raises the temperature in Mumbai, although with lower humidity, the air feels less oppressive." Kapadia added that the city might continue seeing a temperature of 34°C to 35°C until November 8 or 9. However, the absence of clouds is expected to provide some relief at night, with lows potentially dipping to 21°C, resulting in a daily temperature range of about 14°C. He further noted that this diurnal variation could impact vulnerable individuals, as the sudden shifts between daytime heat and nighttime coolness can challenge the body's acclimatisation.

Meteorologists from Skymet Weather, a private forecasting agency, commented on the ongoing warmth, stating, "Mumbai continues to reel under warm and sultry conditions with high humidity levels throughout the day. After the southwest monsoon withdraws, the city undergoes a reversal of wind pattern, with land breeze dominating the night and morning hours. The sea breeze sets in anytime after 12 pm, raising humidity and increasing afternoon discomfort. However, the evening breeze acts as a soother, especially along the coast."

They added that October and November share similar weather patterns post-monsoon: "Day temperatures remain around 33°C to 34°C in both months. Night temperatures, however, drop from 24°C to 25°C in October to around 21°C in November." According to Skymet, "Weather conditions over Mumbai are influenced by patterns in North India, particularly in Punjab and Rajasthan. After a winter anticyclone establishes over Rajasthan in November, cool winds reach North Gujarat, North Madhya Maharashtra and Konkan, including Mumbai. This pattern is still developing, so a slight delay in cooler temperatures is likely. With winter weather over North India expected to arrive later than usual, the Konkan coast and Mumbai may face an extended warm and sultry spell, with conditions likely improving by mid-November.

Spikes across Maharashtra

A recent report by ClimateTech startup Respirer Living Sciences Pvt Ltd shed light on the impact of Diwali festivities on air quality across key cities in Maharashtra, including Mumbai, Pune and Nagpur. The study analysed air quality monitoring data from October 30 (pre-Diwali), October 31 (Diwali), and November 1 (post-Diwali) to assess how festival-related activities influenced particulate matter levels (PM2.5 and PM10). The findings reveal a significant increase in pollution, with PM2.5 levels in each city rising over 50 per cent on average. This analysis not only highlights the environmental implications of festive pollution but also emphasises the urgent need for targeted air quality management during such high-emission events.

PM2.5 levels rise

In Mumbai, PM2.5 pollution rose by 50.3 per cent from October 30 to November 1, jumping from 57.46 μg/m3 to 86.39 μg/m3. Some areas saw even larger increases: Sewri's levels rose by 116.9 per cent, Malad West by 177.2 per cent, and Kandivli West by 97 per cent. Other spots, like Byculla, Chembur, and Deonar, also saw significant rises. Cities like Dhule, Nanded, and Pimpri-Chinchwad experienced even worse spikes, highlighting the statewide impact of Diwali pollution. Respirer CEO Ronak Sutaria stressed the need for better air quality management and public awareness to protect health across Maharashtra, especially for
vulnerable groups.

0-50
Good AQI level