How do forests check air pollution?

Planting trees has many environmental benefits. Carbon dioxide is one of the major gases which contributes to the  pollution.  Forests balance the percentages of carbon dioxide and oxygen in the atmosphere. The increasing amount of carbon dioxide caused by human activities is balanced by a larger intake of carbon dioxide by plants during the process of photosynthesis. Simultaneously, a large amount of oxygen is released. Thus, check the pollution of air.  Besides this, planting of trees also helps in maintaining the temperature of a region, level of ground water etc.