SMOG

Smog is air pollution that reduces visibility. The term "smog" was first used in the early 1900s to describe a mix of smoke and fog. The smoke usually came from burning coal. Smog was common in industrial areas, and remains a familiar sight in cities today.
Today, most of the smog we see is photochemical smog. Photochemical smog is produced when sunlight reacts with nitrogen oxides and at least one volatile organic compound (VOC) in the atmosphere. Nitrogen oxides come from car exhaust, coal power plants, and factory emissions. VOCs are released from gasoline, paints, and many cleaning solvents. When sunlight hits these chemicals, they form airborne particles and ground-level ozone—or smog.This smog is a highly toxic and can cause serious respiratory problems for people who may find it difficult to breath all of a sudden. Smog can also hurt eyes and nose by causing irritation.
In Lahore and its adjoining areas, over the last past years, a smog descends every November/December. It is so thick that even airplane flights to Lahore are canceled as a result.In the last 5 years, this smog has grown way worse, owing to poor air quality and high amount of pollution caused by vehicles and factories. The cutting down of trees and rapid industrialization has not helped matters as well, something that the development-focused authorities should do well to heed as well.Lahore is now considered as one of the most polluted cities in Asia. In winter months, all the pollutants tend to collect in the lower level of the atmosphere due to rains, cold spells and dry condition.Experts state that factories in India across Eastern Punjab are to be blame as well, given their reliance on coal use. The emissions and pollutants from there carry over to this side of the border and make things worse.
 
How to Combat Smog.
Everyone can do their part to reduce smog by changing a few behaviors, such as:-
  •   Keep your windows closed. Be it your vehicle, office, home etc.
  •   Drive less. Walk, bike, carpool, and use public transportation whenever possible.
  •   Take care of cars. Getting regular tune-ups, changing oil on schedule, and inflating tires to the proper level can improve gas mileage and reduce emissions.
  •    Fuel up during the cooler hours of the day—night or early morning. This prevents gas fumes from heating up and producing ozone.
  •    Avoid products that release high levels of VOCs. For example, use low-VOC paints.
  •    Avoid gas-powered yard equipment, like lawn mowers. Use electric appliances instead.