Major environmental problems

The main environmental hazards recognised worldwide are:

A. Resource depletion. Using up non-renewable resources is one of the most serious problems.

• Fossil fuels get the headlines, but water and land are probably being depleted even faster. Groundwater levels are falling sharply across India, especially in Punjab, Haryana and Uttar Pradesh: aquifers filled over thousands of years are emptied in a few decades for intensive farming, industry and cities.
• Rivers have been dammed and diverted, damaging river basins irreversibly; urban water bodies have been filled and built on, destroying natural drainage.
• Topsoil, formed over thousands of years, is lost to erosion, water-logging, salinisation and brick-making.
• Biodiversity habitats (forests, grasslands, wetlands) are shrinking, mainly as farming expands, endangering species unique to India; the tiger population fell sharply despite laws and sanctuaries.

B. Pollution.

• Air pollution from industries, vehicles and the burning of wood and coal at home causes serious illness and death. Indoor pollution from cooking fires (chulhas) is a serious and often overlooked risk in rural homes. The WHO reported that about 7 million people died in 2012 from air pollution exposure, about one in eight deaths worldwide: 3.3 million linked to indoor and 2.6 million to outdoor air pollution.
• Water pollution from sewage, factory effluents and farm runoff of fertilisers and pesticides affects rivers and groundwater.
• Noise pollution in cities, from loudspeakers at events and campaigns, horns and traffic, and construction, has led to court orders in many cities.

C. Global warming. Gases such as carbon dioxide and methane create a 'greenhouse' effect, trapping the sun's heat. Even a small rise in global temperature is expected to melt polar ice, raise sea levels and submerge low-lying coasts, upset ecological balance, and make climates more uncertain. China and India are increasingly significant emitters.

D. Genetically modified organisms (GMOs). Genes from one species can be put into another. Genes from the bacterium *Bacillus thuringiensis* have been put into Bt cotton, making it resistant to the bollworm. GM can also shorten growing time or increase size and shelf-life. But little is known about long-term effects on people or ecosystems, and companies can make sterile seeds that farmers cannot re-use, keeping them dependent.

E. Natural and man-made disasters: the Bhopal gas disaster of 1984 and the 2004 tsunami are recent examples.

Example (new): a town lake that once stored monsoon water is filled in for a shopping complex; the next heavy rain floods nearby streets, and wells in the area start drying up in summer.