An Indian girl reacts as others throw colored powder on her as they celebrate Holi in Ahmedabad, India, Monday, March 5, 2012. Hindus across the country are celebrating Holi, the festival of colors, on March 8. (AP Photo/Ajit Solanki)

Police in Nepal have launched a crackdown on men throwing water balloons at women during the Hindu festival of Holi, warning the pranksters they face jail.

Worshippers in Nepal and neighbouring India are this week celebrating what is known as the festival of colours by daubing friends and relatives with vibrant, scented powders.

But police in Nepal say they have become alarmed by the increasing number of young men hurling water balloons from windows onto women on the streets below.

“We have arrested more than 40 people for throwing balloons filled with dirty water,” Kathmandu Metropolitan Police spokesman Rabi Raj Shrestha told AFP.

“They have done so without the consent of people. They especially harass women. People who throw these balloons will continue to be arrested and could face jail.”

The annual spring festival, which reaches its climax on Wednesday in Nepal, has seen increasing violence in recent years with scuffles breaking out between balloon throwers and angry members of the public.

“We have deployed an additional 500 policemen in Kathmandu. We have checkpoints in several places,” Shrestha said, warning that drunks and cannabis-users would also be arrested.

Holi will be celebrated by millions of Hindus across India on Thursday. - AFP