Indians are marking the 30th anniversary of the Bhopal gas leak tragedy with protests demanding harsher punishments for those responsible and more compensation for the victims of the world's worst industrial disaster.

On Dec. 3, 1984, a pesticide plant run by Union Carbide leaked about 40 tons of deadly methyl isocyanate gas into the air, killing an estimated 15,000 people and affecting at least 500,000 more.

The disaster remains an open wound in India, where many consider Union Carbide's $470 million settlement with the government an insult.

Union Carbide is now a wholly owned subsidiary of the Dow Chemical Co.

Dow says it has no liability because it bought the company responsible for the plant after the cases had been settled.