THE awakening moments of Water, the third and final film of Deepa Mehta's Indian trilogy, shows a boat working its way in leisured poetry across a lilystrewn expanse of water. It's the kind of lazy, meditative camera style we know from films about India such as Jean Renoir's The River and Satyajit Ray's Pather Panchali . . . allegories about man's place in nature that enfold their tragedies among the relentless circling of the seasons. But in Water, Oscar-nominated this year for best foreign film, the tragedy is at the whim of society.

One of the boat's occupants, eight-year-old Chuyia (Sarala), has her head shaved and we see her toes curl in discomfort. She is told that she is now a widow, and what unfolds is an angry, disgusted story about the way human beings treat each other under the mantle of religion. Like Mehta's two previous films, Fire and Earth, this story of India is awash with sociopolitical anger, albeit bathed in lush cinematography and for the most part, restrained melodrama.

Mehta's 1996 film Fire was the first Indian film to deal with lesbianism; her follow-up, 1998's Earth framed the torrents of religious intolerance at the time of India's independence in 1947.

Water is set in 1938 when Mahatma Gandhi's passive resistance was sweeping the country and modernism was beginning to shake free the more unsavoury ancient traditions. For Chuyia, the eight-year-old widow with the newly shaved dome, must spend the rest of her life in an ashram for Hindu widows . . . an impoverished house saturated in stigma. They are seen as pariahs.

People are afraid even to be touched by their shadows. Barely old enough to know what marriage is, she now has to pay for the sins of her past life which, according to tradition, were responsible for killing her husband. As one member of the ashram says when an elderly widow dies: "God willing, she'll be reborn as a man."

But Water is more compassionate humanism than firebrand feminism. It shows that everybody is responsible, including the widows who ensure that the religious laws are obeyed;

this might have something to do with the superstition that a widow who remarries is reborn in the belly of a jackal.

Chuyia is taken under the wing of the oval-eyed, long-haired Kalyani (Lisa Ray) and Shakuntala (Seema Biswas), a thoughtful but deeply religious widow who has ambiguous feelings about their fate. Chuyia is played with incredible impudence by child actress Sarala, who doesn't speak Hindu and had to learn every line by heart. It is her wide-eyed innocence that exposes the ashram for what it is. "Where is the home for men widows?" she asks to loud gasps all round.

Families are implicated because we later learn it is an excuse for them not to feed another mouth.

And then there's the gentry, who have "unnatural concerns for widows". Gulabi, a bitter and elderly matriarch, funds the ashram by prostituting Kalyani.

The implication is clear: Chuyia will face the same fate.

The catalyst for change comes in the shape of a tall, spectacled young man with a heart full of compassion: Narayan (John Abraham) takes one look at Kalyani and falls helplessly in love.

He is a follower of Gandhi and a moderniser, and so has no truck with asking Kalyani to marry him.

"Who decides what is good? Who decides what is bad?" he says. But Chuyia, in her enthusiasm, blurts this to Gulabi who determines to stop it. "We'll be cursed. We must live in purity, " she panics.

Water teems with strong characters. And there is a purity in the way it silently washes superstition away to reveal ulterior motives that operate under the protection of religious fundamentalism. "Disguised as religion it is just about money, " says Narayan. And the film is so incensed about this practice, it doesn't give us space to fume at the tradition of marrying off young girls to older men.

But for all its quiet confidence, the film loses some power in the final reel: it resorts to contrivance and gushing melodrama . . . often the last resort of an insecure dramatist. For Mehta has already done the hard work: the injustice has spoken for itself; the women in the ashram have earned their dignity.