Pollution is the introduction of contaminants into the natural environment that cause adverse effects. It discusses various types of pollution like air, water, soil, noise, and light pollution. The document outlines causes like industries, vehicles, and agriculture. Effects include health impacts and ecosystem damage. It provides measures to control different types of pollution such as treating wastes, using public transport, and limiting fertilizers. The most polluted world cities include Cairo, Delhi, and Beijing. The conclusion is that reducing pollution requires going green.