NEW DELHI — Health workers disinfected wells and distributed chlorine tablets to thousands of villagers rushing back to their homes as water levels receded sharply in northern India, officials said today.

Many defied warnings to remain in relief camps to ensure it was safe to return to their flood-hit homes, said L. B. Prasad, the Uttar Pradesh state director-general of health services.

More than two weeks of monsoon rains across much of northern India, Bangladesh and Nepal have flooded rivers and inundated plains, killing at least 443 people and stranding some 19 million more, officials said.

Villagers have been given chlorine tablets to purify drinking water and were advised to take precautions for the next few days, Prasad told The Associated Press in Lucknow, the capital of Uttar Pradesh.

International aid groups have warned of an impending health crisis if help does not reach millions of South Asians stranded by heavy flooding, amid forecasts of more rain in the devastated region.

With weather clearing this week, aid workers, government officials and the military have rushed food, drinking water and medicines to flood-hit areas.

Stagnant waters left by the floods are a lethal breeding ground for diarrhea and waterborne diseases at an epidemic level, he said.