Air quality in Siliguri

How polluted is the air in Siliguri?

Siliguri is a city that spans areas of the Darjeeling and Jalpaiguri districts in the Indian state of West Bengal. It is situated on the banks of the Mahananda River at the foothills of the Himalayas where it connects with four international borders i.e. China, Nepal, Bangladesh and Bhutan. It also connects the North-East with the Indian mainland and is connected with all other districts of West Bengal. Due to this strategic location, Siliguri soon expanded from the village it once was to the major logistics hub that it is today. In 2011 the population was estimated at being just less than 500,000, but that will have increased over the last 10 years.

At the start of the second quarter of 2021, Siliguri was experiencing a period of air quality that was classified as being “Unhealthy for sensitive groups” with a US AQI reading of 112. This figure is in accordance with recommendations by the WHO (World Health Organisation). The concentration of PM2.5 was 40.2 µg/m³. As this is quite a high figure, the advice given would be to close doors and windows to prevent dirty air from entering the rooms. Those people of a sensitive disposition should avoid venturing outside until the air quality improves. All forms of outdoor exercise should be postponed because poor quality air can affect everybody.

Does the air quality in Siliguri vary throughout the year?

During the winter months from November through to the end of March, Siliguri seems to have a period of “Unhealthy” air according to the latest figures released by the IQAir Company for 2020. Figures were recorded between 55.5 and 150.4 µg/m³. During April, July, August and October, the quality of air was classified as being “Unhealthy for sensitive groups” with readings between 35.5 and 55.4 µg/m³. The remaining 3 months saw a “Moderate” level between 12.1 and 35.4 µg/m³.

Looking back over the figures from previous years it is seen that the air quality is deteriorating. In 2018 the mean annual figure was 44.5 µg/m³ followed by a slight improvement the following year of 39.6 µg/m³, in 2019. However, in 2020, the air quality crossed into the “Unhealthy” category with an average figure of 58.2 µg/m³.

What are the sources of the polluted air in Siliguri?

The city of Siliguri is becoming a victim of pollution day by day. Like Delhi, air pollution is also increasing rapidly here. According to data from the Pollution Control Board, the city has been included in the list of polluted cities in the country. Generally, if the air quality index (AQI) level is up to 200, it is considered to be good. However, the air quality of Siliguri city has been recently recorded at an average of 344. However, an even more alarming level of 415 was recorded soon after that.

It is noteworthy that the population in Siliguri is increasing at an annual rate of 48 per cent. The number of vehicles has also increased by the same proportion. Due to indiscriminate urbanisation, the greenery of this place is becoming compromised daily. In this regard, environmental activists are saying that the time has come to do something about it before it’s too late.

Because of its significance as a transportation hub, this will be a major source of air pollution due to the various forms of vehicle coming here on a daily basis. Not all buses are using clean, sustainable forms of energy. Many of the old local buses continue to use diesel which is particularly harmful when used in older vehicles without modern technology which is much cleaner.

If one goes out on the road, there is so much pollution mainly due to traffic congestion that the eyes get filled up with water. Experts point out that the lack of any administrative effort to discipline the hawkers and traffic is the principal main cause behind the city getting the unwanted top ranking. In the city, the absence of new and alternative roads and flyovers leads to congestion of traffic.

Overpopulation and the ensuing overuse of scarce resources puts heavy pressure on the environment. Under a research project, a team of scientists has been monitoring the quality of air. They have found out that the polluted air generated in industries in northern India travel over 2000 kilometres to reach Siliguri. A huge thick mass of air carrying particulate matter (PM) of less than 2 micrometres, travels to West Bengal under the influence of the strong north-westerly winds. Black carbon concentration over Siliguri and Darjeeling was 3.5 µg/m³. The researchers also analysed that 43 per cent of the founded pollutants are not locally originated. There are at least six major pollutants such as carbon monoxide, nitrogen dioxide, ozone, particulate matter 10 microns or less and 2.5 microns, sulphur dioxide considered harmful to public health and the environment.

What can be done to improve the air quality in Siliguri?

The following suggestions could help improve the air quality in Siliguri. Proper traffic planning can help alleviate congestion. The central control pollution board (CCPB) can check the emissions from vehicles and fine any offender who violates the accepted limits. Diesel vehicles should immediately be converted into gas-powered ones or use the latest technology which includes a comprehensive filtration system. The frequency of the local buses should be increased as they are low smoke emission vehicles. Garbage and waste products should be properly filtered and disposed of in a sustainable manner.

What effect does poor quality air have on health?

Breathing ozone (O₃) and particle pollution (PM2.5) can lead to increased asthma attacks, which can result in visits to the doctor, not to mention missed work and school. Air pollution can increase the risk of both heart attacks and stroke. In 2013, the World Health Organisation determined that particle pollution can cause lung cancer, which is the leading cause of cancer-related deaths. Exposure to air pollution can slow down and stunt lung development in growing children, harming their health now and reducing their lung function as adults. Exposure to air pollution can make it even harder for people with chronic obstructive pulmonary disease (COPD) to breathe. Severe symptoms can lead to hospitalisation and even premature death. Even people with healthy lungs are susceptible to irritation and swelling. Some studies show exposure to air pollution may increase the risk of low infant birth weight and infant mortality. These can be caused by both long-term exposure and short-term exposure to high levels of air pollutants.