Acclaimed director Shekhar Kapur, who has termed his new work "Paani" a mission, says he had written the film 15 years back.

"When first wrote 'Paani'? 15 years ago. But no one thought it would be such a big issue then, " Kapur tweeted Sunday.

"Richard Attenborough said it took him 20 years to get 'Gandhi' made. I guess every director has such a passion, " further posted the 66- year-old.

Known for his Bollywood films "Masoom", "Mr. India", "Bandit Queen", Kapur moved to Hollywood and directed movies like "Elizabeth", "The Four Feathers" and "Elizabeth: The Golden Age".

"Paani" is based in a future world where wars over water have broken out. Water is now owned by international corporations who use thirst as a weapon of control. In one such future city, a young love story breaks all the rules and in the ensuing war, water flows back to its people.

The project kept getting delayed until Yash Raj Films agreed to be the producers of the film. It was reported that Hrithik Roshan will essay the male lead. But no confirmation has been made yet.

"Paani" will go on floors mid-2013 and will be shot in India and overseas. It will have music by the Oscar-winning musician A.R.Rahman.