The Live Earth environmental series return in April with a focus on water - and with a surprise sponsor, the US-based Dow Chemical Company.

Down owns Union Carbide, infamous for the 1984 Bhopal, India, disaster, in which some 15,000 people died when a company pesticide tank leaked.

Dow says it bears no responsibility for the disaster because Union Carbide already paid compensation, though environmentalists insist that Dow is still responsible for cleanup.

Organisers said that the Dow Live Earth Run For Water event will include six kilometre races, concerts, and water-saving related activities to be held in cities around the world, including Buenos Aires, Singapore, Cape Town, Chicago, Hong Kong, London, Los Angeles, Melbourne, Mexico City, New York, and Rio de Janeiro.

Personalities headlining the event include US actress Jessica Biel, environmentalist Alexandra Cousteau - famed undersea explorer Jacques-Yves Cousteau's granddaughter - and Benin singer Angelique Kidjo.

The event "will bring people together around the world, raising awareness about the sources and consequences of the water crisis, locally and globally," Alexandra Cousteau said when announcing the event.

The beauty of the event "is that it gives us a platform to encourage others to be part of the solution to help everyone have access to clean, safe drinking water," said Ms Biel.

The Live Earth concert was first held in July 2007, inspired by Nobel Peace Prize winner Al Gore and his film An Inconvenient Truth about global warming.

"Dow is proud to be the title sponsor for this groundbreaking event," said Ian Barbour, general manager at Dow Water & Process Solutions, a Dow business unit.

In December 1984 a storage tank at a Union Carbide pesticide plant in Bhopal leaked, killing more than 15,000 area residents over the next days. Amnesty International puts the casualty figure as high as 25,000.