Mumbai Deploys GRAP-4 Amid Declining Air Quality Levels — What It Means for Residents

The rising levels of pollution in Mumbai have triggered the Brihanmumbai Municipal Corporation (BMC) to deploy the Stage-4 of Graded Response Action Plan in the most affected areas including Mazgaon, Deonar, Malad, Borivali East, Chakala-Andheri East, Navy Nagar, Powai and Mulund.

Parts of the city that fall into the "very poor" and "severe" AQI ranges are subject to the most recent restrictions.

The GRAP enforced in Mumbai categorises air quality into six levels, with an AQI of 0–50 indicating ‘good’, 51-100 'satisfactory', 101-200 'moderate', 201-300 'poor', 301-400 'very poor', and 401-500 'severe'.

Do’s and Don’ts Under GRAP-4

The BMC has prohibited construction and other dust-generating activities in several high AQI zones mentioned above. Over 50 construction sites have received stop-work notices, while small industries such as bakeries and marble-cutting units have been instructed to adopt cleaner technologies or face penalties, reported Economic Times.

The civic body has also deployed flying squads across all wards. So far, 53 out of 70 inspected sites have been issued notices. These teams, comprise of engineers, police personnel and GPS-tracked vehicles, are monitoring emissions and ensuring compliance with pollution control rule.

In addition, BMC has adopted other measures to curb pollution, including mandating cleaner fuels for bakeries and crematoriums, increasing electric buses in the public transport fleet, ensuring scientific management of construction debris, using mechanised water-sprinkling machines to control roadside dust, reported Economic Times.

This is not the first time the BMC has implemented guidelines to control dust and pollution. In October last year, the BMC issued 28 guidelines which include installing metal fencing and green cloth covering around construction sites to control dust, carrying out water sprinkling, properly storing and transporting debris, installing air quality monitoring devices, and setting up smoke absorption systems, among other measures.

Reasons Behind AQI Spike

Angshuman Modak, climate scientist with the Indian Institute of Technology Bombay, told PTI that the reason behind spike in the AQI level could be attributed to construction activities and vehicular emissions as the main sources of pollution.

Mumbai and its satellite cities are witnessing an urban transformation from multiple Metro rail lines to road works, bridges and other building activities. Slums, chawls, the last of the mills and industrial units are giving way to skyscrapers.

Attributing the worsening AQI to the infrastructure in the city, Sushma Nair, scientist with India Meteorological Department (IMD), told PTI that the temperature inversion and north-easterly winds are a characteristic of this time of the season when there is transition to winter. Conditions favour temperature inversion when clearer skies allow the ground to cool rapidly and wind speeds are low. A dense layer of cold air gets trapped below warm air, preventing pollutants from dispersing.

However, for a metropolis like Mumbai, dense and tall urban structures can interfere with the air flow that can aid in dispersing the pollution, Nair explained PTI.

Political reactions have also surfaced over the worsening air quality, with Shiv Sena (UBT) chief Uddhav Thackeray targeting the state government for the pollution and calling it an outcome of "explosion of corruption" with zero planning aimed at benefitting the contractors.

 (With inputs from PTI.)