What is Smog? 10 States in India with Deadliest Smog

Smog is a type of air pollution that is characterized by a mix of smoke and fog, hence lowering the level of visibility and health impacts. The term "smog" was derived from the merging of "smoke" and "fog," which was used in the early 20th century to refer to atmospheric conditions in industrial cities, especially when it was foggy during the colder months.

Types of Smog

There are two primary types of smog:

Photochemical Smog: It is formed when the sun interacts with nitrogen oxides and volatile organic compounds in the atmosphere. It produces ground ozone, among other air toxins. It is much more prevalent in areas of large urbanization and more traffic and industrialization.

Sulfurous Smog: Often called "London smog", this kind is due to strong concentrations of sulphur oxides mainly resulting from the combustion of fossil fuels like coal. It usually happens during colder periods with a high concentration of humidity.

Health Effects

Smog has severe health impacts, including:

• Respiratory problems like coughing and wheezing
• Eyes and throat irritation
• Strong cases of cardiovascular diseases and lung disorders
• Extremely sensitive reactions for people who already have diseases such as asthma.

States in India With Deadliest Smog

The severe smog conditions of the country fall mainly during the winter months. Reasons for these include stubble burning, emissions coming from vehicles, and industrial pollution. The deadliest states in India against smog are,

• Delhi: This is always featured as one of the world's most polluted cities, with PM2.5 levels usually raising massive margins over the safety limits.
• Punjab: Agricultural practices, especially stubble burning, significantly contribute to air pollution in Delhi and other neighbouring areas.
• Haryana: Like Punjab, it also has severe levels of pollution from agricultural fires4.
• Uttar Pradesh: Industrialization and urbanization have caused tremendous problems in terms of air quality.
• Maharashtra: Vehicle emissions and industrial effluent discharge are the main pollutants in cities like Mumbai.
• Rajasthan: Dust storms and industrial effluent deposits are harming the air quality.
• Gujarat: Industrially developed Gujarat has air pollution at a severe level.
• West Bengal: In Kolkata, severe air pollution occurs primarily due to vehicular emissions and construction dust.
• Tamil Nadu: The city of Chennai faces challenges from industrial pollution.
• Bihar: Rapid urbanization contributes to deteriorating air quality in cities like Patna.

As of November 18, 2024, the Air Quality Index (AQI) in various states of India has reached alarming levels, particularly in the northern regions. Below is a summary of the AQI data for key states affected by severe smog on this date:

Key Observations

• Delhi recorded the highest AQI at 978, categorized as hazardous, indicating severe health risks for all residents.
• Haryana and Uttar Pradesh also displayed extremely poor air quality, with AQI values of 631 and 600, respectively.
• Other states like Punjab and Bihar are similarly experiencing critical air quality issues, with significant levels of PM2.5 contributing to health hazards.

Seasonal spikes occur in smog levels in these states from October to January due to weather conditions allowing pollutants to be trapped close to the ground and increasing the threat of bad health to the local population.

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