Soil pollution is alteration in soil caused by removal or addition of substances and factors, which decrease its productivity and quality of plants and ground water. Negative soil pollution is reduction in soil productivity due to erosion and over use. Positive soil pollution is reduction in soil productivity due to addition of undesirable substances e.g., agrochemicals, industrial wastes, air pollutants washed down by rain, faulty sanitation etc. Pesticides and fertilisers are the two most important types of agrochemicals.