[[ Learning from the Hudson River Experience, we in India need to make any project in river-development, river-beautification, river front development criminally illegal - unless there is 95% of ANY river-budget deployed on the comprehensive river-basin cleaning up activity to make reduction of measurable-water-pollution and revival of measurably-declined-number-of-species-of-river-fish - the 95% determinants in drafting ANY PERMISSIONS to any meddling of government and contractors in the river ecology-geohydrology.

WE IN INDIA NEED TO MAKE RIVER WATER POLLUTION CONTROL A RIVER BASIN WIDE LEGAL IMPERATIVE - taking lessons from the River Hudson River-Revival and then ADAPTING them to Indian Budgets and Conditions without losing the sharp vigilance on those in Government and Private Business who are indifferent to the priority of keeping the river water unpolluted and clean.]]

.(Notes on Hudson River studies and methodologies. Source https://www.dec.ny.gov/lands/77105.html )

.As cities grew along the Hudson (River), their sewage discharges increased. In 1965, New York State voters passed a billion dollar Pure Waters Bond Act to fund sewage treatment. In 1972, the Clean Water Act made cleanup a national priority, providing billions more. The Hudson benefited. Off Manhattan, 150 million gallons of raw sewage entered the river daily until 1986, when the North River sewage treatment plant began operating. Bacteria concentrations then declined markedly.

.The Clean Water Act (1972) also limited industrial discharges. In the years following the law's passage, polluters gradually came into compliance. The Hudson's color at Tarrytown once matched the paint applied to vehicles at a General Motors plant there; now such scenes are unthinkable.

.Before cleanup, sewage, paper mill discharges, and other organic wastes fed bacteria, swelling their populations. Bacteria consume dissolved oxygen that fish need to breathe. Near Albany in summer, 1970, a study found so little dissolved oxygen that the few fish seen were "swimming slowly at the surface, gulping air, and disturbing an oil film which covered the water surface." After treatment began, 3,314 fish of 27 species were collected there in summer, 1975.

.Rain sweeps automotive fluids and trash from parking lots into the nearest storm drains and eventually the river. Fertilizers, pesticides and animal wastes wash off lawns and farm fields. Soil left bare of plants erodes into streams. Controlling this pollution requires diverse and coordinated efforts by government and private citizens. Watershed planning can be a particularly effective means of addressing such problems.

(More notes on the Hudson river cleanup: Source: https://www.nytimes.com/1996/06/09/nyregion/river-reclaimed-reversing-pollution-s-toll-first-twoarticles-shaking-off-man-s.html?auth=link-dismiss-google1tap

Other sources of carbon, nitrogen and phosphorus developed as towns and cities expanded along the Hudson and its tributaries and began dumping human waste -- an especially rich energy source -- into the system. Bacteria fed on the waste and consumed so much oxygen that none was left for other species in many parts of the river. This created the Hudson's dead spots of the 1960's and 1970's.

One notorious example was the Albany Pool, a stretch of 20 to 30 miles just south of the Troy dam, where fungus from sewage coated the buoys, a strong odor of sewage assaulted the nose, fish were killed by lack of oxygen, oil slicks covered the surface and animal parts from an upstream packing house floated by. So foul was the pool that as Mr. Boyle noted in his book, men "grit their teeth and women left the room," according to press reports of hearings in the late 1960's on the pool's problems.

Levels of dissolved oxygen in the water have increased up and down the river, a fundamental indicator of health and a sure signal that less raw sewage is being discharged. At 42d Street, for instance, today's oxygen levels are about double what they were in 1960, according to the New York City Department of Environmental Protection.

The cleaner river is due partly to New York State's pioneering pollution laws but especially to the Clean Water Act. In just the stretch of the Hudson from Poughkeepsie to the Battery, for instance, the Federal Government has spent about $1.25 billion under the act's provisions since 1973 to improve municipal sewage treatment.