In 1970, a survey of gharial habitat along the Kosi river performed by a group of scientists from the Zoological Survey of India, found that the crocodiles were poached rampantly, killed for their skin or even trapped inadvertently in fishing nets. Shifting of the Kosi's course and artificial embankments also contributed to the decline in the reptile's population as did monsoon waters, which would flush gharials down to uninhabitable places every year.

In 1974, another survey confirmed all the scientists’ worst years. That year the gharials numbered less than 200 in the wild. Exact figures aren't available, but conservationists estimate that in the 1940s, the Indian subcontinent was home to somewhere between 5,000 to 10,000 gharials spread across India, Nepal, Pakistan, Bhutan, Bangladesh, and Myanmar.

The Convention on International Trade in Endangered Species recommended a ban on the killing of all crocodile species, and their translocation to protected areas. The Indian government took up this recommendation in earnest. The gharial was accorded protection under the Wildlife Protection Act (WPA), 1972. Project Crocodile was started in 1975 with the aid of the United Nations Development Program and FAO. Stretches of the Mahanadi, Ganga, Girwa, and other rivers inhabited by gharials were declared protected areas.

The project included an intensive captive breeding and rearing program to create a large crocodile population that would be ultimately translocated to these reserves. An acute shortage of gharial eggs was overcome by their purchase from Nepal. A male gharial was flown in from a zoo in Frankfurt, West Germany, to become one of the founding animals of the breeding program. Sixteen crocodile rehabilitation centers and five crocodile sanctuaries-National Chambal Sanctuary (NCS), Katerniaghat Wildlife Sanctuary (KWS), Satkosia Gorge Wildlife Sanctuary, Son Gharial Sanctuary and Ken Gharial Sanctuary-were established between 1975 and 1982.

Eight hundred and seventy-nine gharials, 190 estuarine crocodiles, and 493 mugger crocodiles were released in the wild in that period. A Crocodile Breeding and Management Training Institute was set up in Madras in 1980 to train managers of crocodile stations. By 1991, 12,000 gharial eggs were collected from wild and captive breeding nests, and over 5,000 gharials reared to about a meter or more in length and released in the wild. Over 3,500 of these were released in NCS, the biggest gharial reserve in the country sprawling across 425 km in the provinces of Uttar Pradesh, Madhya Pradesh and Rajasthan.

The program was hailed the world over as a conservation model and that sealed the fate of the gharial. In 1982 a report by Antoon de Vos, a wildlife biologist, for the FAO/UNDP pronounced Project Crocodile as one of the most successful conservation projects in the world. And in 1991, the Union ministry of environment and forests felt that the project had served its purpose, and stopped funds for its captive-breeding program. Funds were also withdrawn for the egg collection program. The thousands of crocodiles seen in various rearing stations and captive breeding centers clearly attested to the success of the project.

De Vos had suggested stepping up the monitoring of released gharial to determine the continued effectiveness of Project Crocodile. In 1997-1998, monitoring exercises by the forest departments of Madhya Pradesh, Rajasthan and Uttar Pradesh located over 1,200 gharials and over 75 nests in NCS. But no survey was carried out between 1999 and 2003. The survey in 2003 showed catastrophic results: only about 200 reproducing gharials remain in the wild, 90% of them in NCS, and a few survivors in Nepal.