Pollution.

With the growth of population the atmosphere has become polluted. Industries have greatly added to this pollution. The air around us has become dirty. The content of poisonous gases has increased. Towns and cities have expanded rapidly. More and more space is being used for building houses and factories. More and more people are coming to the towns and cities. The houses are in short-supply: so they live in open or in huts. They go for nature call in the open. This causes pollution. There is lot of traffic, buses, cars, scooter, motor cycles are multiplying. They use diesel and petrol. Their smoke pollutes the air. There are big and small factories using coal, sending poisonous gases into the air. This has caused pollution. We should grow more trees to control pollution.