In 2004 , while reading Sanjoy Hazarika 's book '' Bhopal : Lessons of a Tragedy '' , Ravi Kumar got the idea of making a film based on the Bhopal disaster . The disaster is considered the world 's deadliest industrial disaster . Seeing that very few people of the newer generation knew about the disaster , Kumar decided to make a film based on it . He chose several well known actors for the film because he felt that this provided more chances of showing the " story to the world . " He wanted to cast Sheen for the role of Anderson , because of his political views and acting skills . Tannishtha Chatterjee and Rajpal Yadav were also cast for the film . Sienna Miller was previously attached to the project , but later dropped out and her role was given to Mischa Barton . In December 2008 , it was confirmed that Barton , Martin Sheen and Kal Penn were filming in India for the project . A copy of the script was sent to Penn , who agreed to join the project . Penn played the role of an Indian journalist and learnt Hindi from an instructor . In January 2009 the film 's shooting was wrapped up . Initially , the film 's story was written like a thriller and then dramatic elements were added to the film . Kumar wanted to depict Anderson as a victim of organisational error of judgement but Sheen insisted that Anderson should be depicted as a guilty and so he rewrote some of the scenes . Made on a total budget of US$ 12 million , the film was shot in Hyderabad 's Charminar area and Golconda Fort , Mumbai and the Union Carbide factory in Bhopal during a course of 18 months . A few scenes were also shot in Los Angeles . Hyderabad was chosen since it bore great resemblance to Bhopal in terms of its Mughal influence and architecture . Only a few important scenes were shot in Bhopal while the majority were shot on different factory locations and sets in order to create the setup for the period
Bhopal disaster
Bhopal disaster
Bhopal: A Prayer for Rain