Why Air Quality in Delhi NCR deteriorate during October & November?

We all know about the high levels of pollution our capital city faces during the winter. But have you ever questioned why Delhi is worst affected by air pollution every winter season?

There are several reasons as to why, and we are here to discuss them with you so that you can be aware of what kind of environment you are living in and is it right or good enough for your health.

The onset of winter brings along the problem of air pollution year on year. Not just in Delhi but even in other cities across India. The cold winter air is much denser than the hot summer air, this leads to winter inversion. During summer, the lowest layer of the atmosphere is warmer and lighter as compared to winter, which makes it easy for air to rise upwards.

As a result, the pollutants are carried away from the ground. However, during winter, the air near the atmosphere of the earth is dense and cooler. The warm air traps the cool air and forms an atmospheric lid, which is known as inversion.

The vertical mixing of air happens within this layer, as a result of which the pollutants disperse back in the atmosphere. The effects of inversion are strong at night for which the air quality deteriorates at night. This is the reason why experts advise you to avoid going for morning walks or exercise in the morning as the pollution levels are high.

The dense winter air traps all sorts of pollutants in it. Smoke and fog come together to form smog. This smog is hazardous in many ways, not only does it hamper the visibility of drivers but it is also hazardous to inhale. Delhi is landlocked and the air doesn’t have anywhere to go. The wind speeds are slow during this time and thus the polluted air stays in the capital for the longest time.

Air Quality Index (AQI) of Delhi deteriorates due to the constant pollution from transport, dust, industrial and episodic sources including firecrackers and stubble burning. According to the System of Air Quality and Weather Forecasting And Research (SAFAR), the contribution of stubble burning has increased to 19-22% in Delhi's pollution.

Stubble burning is an easy and cost-effective way for farmers to clear the stubble left on their field after the paddy harvest. It involves little or no cost. Stubble is often worthless for a farmer since it doesn’t form good animal fodder. It could be used as biomass but there are very little or no biomass facilities in most areas and extraction of stubble involves costs like investment mechanized machines which most farmers can’t afford.

Along with the stubble burning, another major contributor is firecrackers during Diwali. Last year several restrictions were imposed on the sale and bursting of firecrackers but it doesn’t seem to be enough. Fireworks cause extensive air pollution in a short period, they leaving metal particles, dangerous toxins, harmful chemicals and smoke in the air for hours and days. Some of the toxins never fully decompose or disintegrate, rather they hang around in the environment, poisoning all they come into contact with.

According to India's Centre for Science and Environment, air pollution caused by firecrackers on Diwali across India was linked to the 30-40% increase in breathing discomfort to humans.

So, with all these problems that we know about, do we also know of a solution? Yes, thankfully we do. 

The best thing for you, as an individual, is to install a good air purifier to survive the wrath of pollution in the winter season. Air purifiers have been proved as an effective solution to mitigate indoor air pollution and to provide air suitable for breathing in. Install an air purifier to protect yourself from various health problems the winter air brings with it.