What’s making Mumbai gasp for air? Answer: Construction, vehicular emission, road work

  • Badri Chatterjee, Hindustan Times, Mumbai
  • Updated: Apr 14, 2015 16:01 IST

For the past few years, residents of buildings surrounding a bakery at Bhalerao Marg, between Girgaum and Charni Road, have been choked by thick black smoke from the wood-burning ovens, which are used five times a day.

Hemant Sukhathankar, a resident of a building opposite the bakery, said the sea breeze pushes the smoke inside his home, forcing him to keep doors and windows shut. “It makes breathing difficult, and residents of the area are suffering.”

Burning of fuel, garbage and wood, vehicular emissions due to traffic congestion, dust from construction activity and road development are releasing toxic pollutants into the air, that Mumbaiites inhale every day. The Central Pollution Control Board (CPCB) last conducted a large-scale assessment of pollution levels across the country, including Mumbai, four years ago. There has been no data since then, by way of an annual report by either the CPCB or the Maharashtra Pollution Control Board (MPCB).

The most dangerous components in polluted air are Suspended Particulate Matter (SPM), including tiny particles called Respirable Suspended Particulate Matter (RSPM), which can be inhaled into the lungs. Oxides of Nitrogen (NOx), which is an important constituent of RSPM, is released by automobiles, power generation plants and road work equipment. Another hazardous component is Carbon Monoxide (CO) which is released by combustion engines. The gas reacts with haemoglobin in the blood, reducing its capacity to carry oxygen.

According to the Air Quality Assessment, Emission Inventory Studies in Mumbai conducted in 2010-11 by the CPCB and the National Environmental Engineering and Research Institute (NEERI), bakeries emitted 11,384 tonnes of Carbon Monoxide (CO) into Mumbai’s air in the year of the study. Open burning emitted 2,292 tonnes of the gas, while burning of garbage at landfills released another 9,082 tonnes.


The study found that annually, particulate matter (PM) emissions were the highest from roads that were under construction, with 4,761.4 tonnes of dust being released from them, followed by that from paved roads, with 3,163 tonnes being released. Open burning in landfills sent 2,906 tonnes of PM into the air, while construction activity and bakeries contributed 2,288.9 tonnes and 1,554.6 tonnes of PM respectively.

“Finer particles come from combustion through burning of various materials such as fuel, garbage and wood at bakeries and crematoriums. They emanate black smoke, which causes chest congestion,” said Indrani Gupta, senior assistant director, NEERI.

Another source of high CO and PM emissions is unregulated parking. A recent study conducted by the Mumbai Environmental Social Network has revealed that indiscriminate parking is taking PM in the air to 17 times the safe limit, and CO to six times the acceptable levels.

Rishi Agarwal, environmentalist, said, “All the roads where paving, restructuring is being done across the city, and all buildings being broken down, are perhaps the main causes of increase in dust levels.”

At the Marine Drive, where the road is being reconstructed, an air compressor is being used to blow out the dust. “Instead of using vacuum technology at an iconic road like Marine Drive, the authorities are using this instrument before applying asphalt, leading to copious amounts of dust in the air. Vacuum technology should have been used, which would have been slightly expensive, but eco-friendly,” said Agarwal.

The study conducted by CPCB and NEERI also showed 19,708 tonnes of oxides of Nitrogen (NOx) were released in a year from locomotive areas where the Western Railway (WR) and the Central Railway (CR) have a presence. Railway authorities, however, denied contributing to air pollution levels, saying their services, in fact, took commuters away from the roads, reducing automobile emissions. “On a daily basis, both CR and WR carry 80 lakh commuters. Imagine the pollution levels if the same number of people started using road transport,” said Narendra Patil, chief public relations officer, CR. “The pollution levels recorded have to be from outside the station areas, from motor vehicles and hotels.”

The study also looked at pollution in seven sites at Colaba, Mahul, Andheri, Mulund, Dadar, Khar and Dharavi, over a period of 30 days each in three seasons. Levels of SPM were highest in Dharavi at 500 micrograms/cubic metre of air (µg/m3), followed by Mulund at 400µg/m3. The permissible limit for SPM is 100 µg/m3.

PM2.5 levels were calculated below 200µg/m3 for all seven locations, while PM10 was the highest in Dharavi and Mulund, both above 200µg/m3. Levels of NOx and SO2 were both below the standard limits at all seven locations. Permissible levels of PM2.5 and PM10 is 100 µg/m3, while that for NOx and SO2 is 80µg/m3.

Rakesh Kumar, chief scientist, NEERI, said, “Pollution in Dharavi was caused by plastic being burnt in the area. In Mulund and Deonar, smoke from dumping grounds caused a rise in levels.” Recent fires in the Deonar dumping ground have pushed up pollution levels in the area yet again.

“We found sites where road construction was the cause of pollutants in the air, especially in the suburbs. The values for hotspots like bakeries and crematoriums may have changed since the study, but they are reasons for increasing pollution levels,” said Kumar.

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