In news: As of November 27, this year, 3.22 percent of rural habitations across all states and UTs, accounting for 3.73 per cent of the population, were consuming drinking water with quality issues, according to data tabled by the Ministry of Jal Shakti in Parliament.

Findings of the data:

  • Iron is the most common contaminant of drinking water, with over 18,000 rural habitations affected, followed by salinity that affects roughly 13,000 rural habitations, arsenic (12,000), fluoride (nearly 8,000) and heavy metal.
  • Rajasthan has the highest number of rural habitations affected by contamination.
  • West Bengal has the highest number of rural habitations affected by arsenic contamination, at 6,207, followed by Assam (4,125), Bihar (804), Punjab (651) and Uttar Pradesh (650). 
  • Assam has the highest number of rural habitations affected by iron contamination, at 5,113. It is followed by West Bengal (5,082), Tripura (2,377), Bihar (2,299) and Odisha (2,100)
  • States and UTs that are not affected by any of these contaminants include Andaman & Nicobar Islands, Goa, Gujarat, Himachal Pradesh, Ladakh, Manipur, Mizoram, Nagaland, Puducherry, Sikkim and Tamil Nadu.

Water contamination in India: In the 'Composite Water Management Index' report, the NITI Aayog pointed out that nearly 70 percent of India's water is contaminated.

  • The major hazardous metals of concern for India in terms of their environmental load and health effects are: lead, mercury, chromium, cadmium, copper and aluminum. 
  • Their source is mostly anthropogenic — industrial activity and vehicles. The most common metal pollution in freshwater comes from mining companies. They usually use an acid mine drainage system to release heavy metals from ores, because metals are very soluble in an acid solution.
  • Natural causes like seepage from rocks, volcanic activity and forest fires can also be contributing factors.
  • Heavy metal toxicity can cause chronic degenerative diseases — the symptoms being mental disorders, pain in muscles and joints, gastro-intestinal disorders, vision problems, chronic fatigue, and susceptibility to fungal infections. Geno-toxicity and cancers can also occur. Methemoglobinemia is caused by nitrate in drinking water.