I very much welcome this development. India has a long tradition of respect for all forms of life and particularly animals, which are in many cases integrated in the Hinduist religion and enjoying this or that kind of protection therefore. But unlike cows or monkeys, dolphins, belonging to the sea, never before were integrated in any meaningful way and yet they are (at least some dolphin species) some of the most intelligent beings on Earth, which may only lack a civilization for less important reasons such as the lack of hands or the impossibility to set up a fire in the water, not for lack of intelligence nor sensibility.
The main practical effect of this new legislation is a ban on dolphinariums, which are equivalent to human slavery. Dolphin slaves usually come from violent hunts in Japan, Russia or other Pacific Ocean countries.
"They drive groups of dolphins into shallow bay areas where young females whose bodies are unmarked and are thought to be suitable for display are removed. The rest are often slaughtered."
Dolphins know well that they are being held captive and the narrow confines of even the best aquarium can only drive them depressed and even mad, hurting themselves in desperate attempts to swim away from their prison.
There have been large animal rights demonstration in India, especially in the city of Kochi, where a new dolphin circus was to be opened. The result is this legislation which follows the spirit of the Helsinki declaration of cetacean rights.
An issue that remains open is the most delicate situation of the Ganges dolphin, one of the few freshwater species, which is seriously endangered.