Bollywood stars have joined calls for Mumbai to temper celebrations and reduce water wastage during a riotous Hindu festival this week, as millions of Indians face their worst drought in decades.

The Holi festival takes place on Wednesday at a time when central parts of Maharashtra state, of which Mumbai is the capital, are reeling under a severe water shortage with no rain due until the monsoon in June.

Revellers enjoying the "festival of colours" have been urged to cut down on water usage during the festival, which is normally celebrated with wild "rain dances" and the throwing of buckets of water, water-filled balloons and paint.

"Water shortage in Maharashtra... and it's only March. What will happen in Summer? Save water! Play a dry Holi!!" wrote cinema veteran Amitabh Bachchan to his hordes of followers on Twitter.

Holi, a public holiday, marks the arrival of spring and is especially popular in northern India and other parts of the world with large Hindu communities.

Bollywood is known to throw lavish Holi parties, but celebrations are expected to be toned down this year. Television show producers say they have cut back their depictions of the festival to avoid water wastage.

Actor Riteish Deshmukh tweeted that the "need of the hour is to save water", while popular TV host Mini Mathur wrote: "The mere thought of rain dances in the wake of the water crisis is creepy and tasteless."

University students in Mumbai have taken to the streets to campaign for a water-free festival, although calls for a dry Holi were deemed "absurd" and a lip-service measure by food and trade policy analyst Devinder Sharma.

"If people are so concerned about drought, ban washing of cars in the cities," he said on Twitter.

Municipal authorities are not planning to cut water supplies on the day of Holi despite calls for them to do so, but they are urging moderation and reportedly not allowing tankers to supply extra water.

A similar problem was faced during 2010's Holi festival when a weak monsoon the previous year left Mumbai with a chronic lack of water.

Authorities attribute this year's crisis to two successive poor monsoons, although critics blame official ineptitude and corruption for exacerbating the natural water shortage.

In Nepal, also celebrating Holi, police said they arrested more than one hundred people for various offences during festivities which have already begun there.

Some were held for throwing water balloons at people and applying colours to their faces without consent, although exact numbers were not clear.

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