Threats to biodiversity include the burning of fossil fuels and clearing forests and other wild lands for industrialized agriculture. More direct human interventions such as poaching and hunting can also have a serious effect. Deforestation and land clearing affect biodiversity by direct removal of species. Direct removal of species, either as a result of land clearing or of exploitation for human use, alters resource availability, such as shelter and food, for higher trophic levels. Air pollution can directly contaminate the surface of bodies of water and soil. This can kill crops or reduce their yield. It can kill young trees and other plants. Sulfur dioxide and nitrogen oxide particles in the air can create acid rain when they mix with water and oxygen in the atmosphere. In some species, transitions between the stages in their life cycles can be triggered by changes in environmental conditions. As many plant species require seasonal exposure to cold temperatures for seeds to germinate. According to the International Union for Conservation of Nature (IUCN): India is a megadiverse country with only 2.4% of the world's land area, accounts for 7-8% of all recorded species, including species of plants and species of animals.There are about 45,000 species of plants, which is about 7% of world's total.