Q.Excess of fluoride in drinking water causes:

Water quality is judged across physical, chemical, biological and aesthetic characteristics, and water pollution occurs whenever a change in these makes water harmful to the organisms that consume or live in it -- effectively, water becomes 'polluted' once it is unfit for its intended use. Sources are classified as point sources (traceable discharges like factory effluent and sewage pipes), non-point sources (diffuse inputs like acid rain and agricultural run-off) and oil leaks/spills, or by sector into municipal, industrial and agricultural wastes; a real 2017 cargo-ship collision off Ennore, Chennai spread oil sludge along 34 km of coast. Water pollution destroys aquatic ecosystems and niches, disrupts food chains (enabling biomagnification of pollutants like lead and cadmium), kills organisms directly (oil films raise BOD/COD and clog gills), spreads diseases like hepatitis, typhoid and fluorosis, and triggers eutrophication and algal blooms, including lethal red tides. India treats clean water as a fundamental right; control rests on the …