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Tuesday, Nov 19, 2019

Gurugram fights pollution without data or plan

gurugram Updated: Nov 04, 2019 00:05 IST
Sonali Verma
Sonali Verma

Since 2012, Gurugram, a city of at least 25 lakh people—declared the most-polluted in the world a Greenpeace report in 2018—has been dependent on just one government-owned air quality monitor for monitoring overall air pollution.

The Central Pollution Control Board’s (CPCB) criteria require cities with a population of 10 lakh or more to have a minimum of three monitoring stations. As per this criterion, Gurugram should have at least nine monitoring stations. But, all plans by the CPCB to install a citywide network of air quality monitoring devices have mostly remained on paper. The most recent in such plans was the one announced by officials of the Haryana State Pollution Control Board (HSPCB) in October when they said that at least two new monitors would be installed before the year ends.

Lack of adequate number of monitors in Gurugram ensures the available official air quality index (AQI) is neither accurate nor does it provide a real-time picture of the city’s overall air quality. Experts said this has resulted in insufficient ground-level implementation of pollution-control measures.


The only air quality monitor at Vikas Sadan in Sector 11 measures pollution levels in the area within a 5km radius, which includes Rajiv Chowk, Civil Lines and Sectors 44 to 48. However, the air quality index for this area is highly unlikely to be representative for all of Gurugram which is spread across 738 square kilometre, experts said. For instance, this figure can’t possibly denote a realistic level of air pollution levels in the outskirts of the city, where the population is now increasing and thus, construction is also higher. Therefore, detailed, area-wise air quality indices need to be ascertained, experts said, adding that authorities need to determine hotspots and constantly monitor air quality at these places.

Additionally, it has often been alleged that the Vikas Sadan monitor malfunctions frequently and thus provides inaccurate AQI data.

Recently, on the day after Diwali, the CPCB’s AQI bulletin, which lists pollution data from all monitoring stations in the country, showed that Gurugram had an AQI of 372 (very poor), which was the same as the level of PM2.5 on that day. But data later ratified by the HSPCB, after taking into account all pollutants, put the AQI at 299.

“Either data from the air quality monitor is wrong or the way the AQI is being calculated is wrong. It is done automatically and might need some correction,” HSPCB senior scientist Rajesh Garhia had then said. However, Garhia retracted his comment on October 31 and said all data was accurate.

Experts said these glitches happen because of improper maintenance.


If one goes by CPCB’s AQI data for Gurugram, citizens breathed much cleaner air in October this year as compared to the same period in 2018. On most days of October—the month that sees the national capital region’s first spell of severe air pollution—the AQI in Gurugram was the lowest in the region. But, privately-owned air quality monitors installed across several spots in the city showed much higher AQI readings on days when the CPCB monitor recorded low AQI.

On and after October 10, when AQI was ‘very poor’ in other NCR cities, including Delhi, Faridabad, Ghaziabad and Noida, Gurugram’s AQI was still in the ‘moderate’ and the lower end of the ‘poor’ category, showed CPCB’s AQI bulletin.

This year, city’s AQI crossed the 200-mark on 14 days, while last year it had crossed the 200-mark at least 24 times, even touching the ‘severe’ category, i.e., beyond 400 (when air pollution affects healthy people and seriously impacts those with respiratory diseases) twice. As per CPCB data this year, October ended with no ‘severe’ AQI days.

Air quality experts said that irrespective of what the CPCB data suggests, there’s not much to rejoice about. While all of NCR recorded a much lower AQI this pollution season than last due to meteorological factors, experts said there can’t be a huge difference between neighbouring cities where geographical factors were more or less similar.

“Meteorological factors, such as wind speed, temperature across the region, were largely similar in October. A large difference in the AQI of other NCR cities and Gurugram is highly improbable and can’t exceed 20-30 points,” city-based air quality expert Sachin Panwar said, adding that experts and residents, who regularly monitor air quality in the city, have been flagging the faulty readings from the Vikas Sadan monitor for a long time.

Panwar said he suspects particulate matter (PM) analysers of the Vikas Sadan monitor are not caliberated and thus, report faulty data. Experts added that sensors of air quality monitors need regular maintenance and should ideally be caliberated every six months.

HSPCB’s Garhia, however, said the instrument is caliberated every six months and is being maintained as per requirements.

Several studies have found that errors in PM monitoring primarily due to incorrect caliberation.


How bad or good is the quality of air we breathe can be understood by monitoring data and interpreting it vis-a-vis the air quality standards. The Vikas Sadan monitor is an automatic, continuous ambient air quality monitoring station (CAAQMS) that monitors pollutants through different analysers generating data every minute and disseminating them digitally. The CAAQM stations collect the data of eight pollutants (SO2, NO2, PM10, PM2.5, ozone, lead, carbon monoxide and ammonia), except metals, such as benzene, arsenic and nickel and BaP.

“The eight pollutants are measured on a daily basis and are compared against the national air quality standards. But the method of measurement for each pollutant may vary,” Dipankar Saha, scientist at the CPCB lab, said.

Another possible explanation as to why privately owned air quality monitors in the city show a higher reading could be that they don’t have an adjustment for humidity, Panwar said. “Water droplets are particles that can show in the AQI readings, especially on private monitors as they don’t have a correction for humidity. So if the humidity is high, the AQI tends to be on the higher side,” he said.

However, the level of humidity in the last week of October was around 50%.

Namita Gupta, founder of Airveda which has low-cost monitors across the city, said she, too, has reasons to doubt the AQI data from the Vikas Sadan monitor for being too low on days when other monitors record high level of pollution. “The difference between the CPCB monitor and the private laser monitors should be in a range of 10%. But the difference has been much higher,” she said.


Accurate, historical air quality data of a city is important for policy changes. Steps to combat air pollution fall short if such data is lacking or missing, experts said, adding that another reason why ambient air quality should be monitored is to create public awareness around environmental conditions. Without such data, targets to reduce pollution, area-wise milestones and compliance measures can’t be met, said members of the Environment Pollution (Prevention & Control) Authority (Epca).

In meetings of the CPCB task force, the performance of Gurugram has been found to be sub optimal in implementation of the Graded Response Action Plan (Grap) that comes into force every winter to mitigate pollution.

According to a January report by Greenpeace, titled Airpocalypse III, several cities in India which had dangerous levels of particulate matter pollution were left out from the purview of the NCAP; no city in Haryana was is named in the list.

Additionally, Epca member and IIT Delhi scientist Mukesh Khare pointed out that Gurugram doesn’t feature in the CPCB’s list of 102 non-attainment cities that have consistently showed air quality poorer than the national ambient air quality standards. The list includes Delhi, Varanasi, Bhopal, Kolkata, Noida, Muzaffarpur and even Mumbai. Environmentalists have criticised the board for leaving out cities that were equally polluted, if not more.

“If Gurugram were in the list, officials would have been forced to take appropriate action to monitor and curb pollution. Without a specific action plan, steps remain inadequate. Gurugram urgently needs more air quality monitors and that locations where the existing monitors are installed also seem erroneous,” Khare said.

While authorities in Gurugram said anti-pollution measures are taken under Grap every winter, as per the Epca’s order, they failed to list policy changes around the issue that have been taken or will be taken.

“Interventions under Grap have are being taken. Departments have been actively tracking and penalising violators to enforce the rules,” Gurugram deputy commissioner Amit Khatri said, adding that long-term policy changes were under the purview of the Gurugram Metropolitan Development Authority (GMDA), and referred to the pollution action plan prepared for Gurugram by the HSPCB earlier this year.

GMDA officials did not respond to repeated requests for a comment.


Dipankar Saha, former head of the CPCB’s air quality lab, offered a broad solution to the problem of air quality monitoring. “We need a combination of automatic and manual systems to track air quality,” he said. Automatic systems, like the one at Vikas Sadan, provide real-time data. “These need to be supplemented with enough manual testing, which involves collecting air samples and testing them in a lab,” Saha said.

Unlike automated systems, which are only quantitative, manual testing is necessary to ascertain the exact nature of airborne pollutants. “It will not only tell you how much PM2.5 you are breathing, but also tell you how toxic the PM2.5 really is,” Saha explained. Manual testing is especially important in winter months, when secondary aerosols in the air create smog.

As an interim measure, air quality experts suggested a second monitor be installed at the same spot in Vikas Sadan to check the accuracy of the existing monitor, and that the CPCB start providing certification to private monitors. 

“It will lend credibility to our data and make those, who own private monitors, more accountable,” air quality expert Gupta said.

Other cities have taken significant steps in monitoring and generating air quality data and making it available to the public, experts said, quoting Kolkata as an example where studies have been conducted to generate specialised data on unregulated pollutants such as air toxins. Delhi, too, has a robust system of air quality monitors, both private and government-owned, and has technology that provides advance daily forecast of the expected level of air pollution.

“Air quality in cities is typically and significantly influenced by outside sources,” Khare said, adding that addressing the problem requires moving the conversation towards addressing pollution at a regional ‘airshed’ level.

“Instead of having different action plans for each NCR city, the region should be defined as an airshed so that so policies apply in all towns leading to better pollution control,” Khare suggested, adding that Beijing, which has defined an airshed to manage its pollution problem, is a model to look up to.

An airshed is an area within which the air frequently is confined or channeled with all parts of the area, thus being subject to similar conditions of air quality.