A Bhopal gas disaster survivor holds a placard during a protest rally in Bhopal Dec. 2, 2014.
The Bhopal industrial disaster killed about 4,000 people on the morning of Dec. 3, 1984. The death toll over the next few years rose to about 15,000, according to government estimates.
Thirty years later, many of those who were exposed to the gas have given birth to physically and mentally disabled children. For decades, survivors have been fighting to have the site cleaned up, but they say the efforts were slowed when Michigan-based Dow Chemical took over Union Carbide in 2001.