NEW DELHI -- Indian elections began in late April, but power has already shifted in the world's largest democracy -- to the 23 justices of the Indian Supreme Court.

Though the election takes two weeks, most signs point to the emergence of another weak coalition government, probably led by the Bharatiya Janata Party, a Hindu nationalist group. Yet it almost doesn't matter how the elections turn out, because the real work of cleaning up India proved too much for the politicians years ago. The Supreme Court has stepped into the breech.

In a constitutional coup of sorts, the high court has issued some extraordinary rulings in the past year, usurping the feckless government's powers in order to get things done. Court action in such matters as cleansing the nation's air, rivers and blood supply to commandeering a bribery investigation of high public officials underscore India's singular advantage over rival countries in the global-development race: its rule of law.

On a steamy New Delhi day, about 100 lawyers in black robes mingle outside the Supreme Court building, waiting for their case numbers to flash on a giant scoreboard. Each morning at the building's dozen courtrooms, the day's docket lists 60 to 80 cases for argument before each two or three justice panel.

Inside Courtroom No. 2, Justice Kuldip Singh hounds the advocate general of the West Bengal state about garbage. A local bar association has petitioned the court to compel the state to clean up Calcutta and its environs, one of the world's most crowded and polluted megacities. Justice Singh, a burly Sikh with a white turban and a roving gray beard, demands to know why a court order for West Bengal to prepare a waste-disposal plan for a particular building project has been ignored. He orders the local building commissioner to appear in court in two weeks to present a detailed plan for dumping the building's trash.

"We are very strong and long-armed," Justice Singh replies, to a mild protest by the West Bengal advocate general before reaching for the next case.

"The Supremes," as the Indian justices are known, are on a roll. Though routine cases still may take years to hear, the court is wading quickly and aggressively into pressing contemporary issues. It has ordered special investigations into the involvement of police in ethnic killings and disappearances; the role of cabinet ministers in allotments of coveted public housing; and the links between businesses and political bribes.

An unprecedented 26 politicians have been indicted for bribery this year, including seven cabinet ministers, who were forced to resign. Lower courts are also flexing their muscle. One district court jailed two members of Parliament for having mob connections, breaking a taboo against locking up lawmakers. Another court convicted a former cabinet minister of fanning ethnic riots in the mid-1980s.

Last month, Supreme Court justices closed a 1974 loophole in India's election law that allowed candidates to circumvent spending caps by routing unlimited contributions through political parties. The court also called tax authorities "wholly remiss" for failing to audit political parties in more than 15 years.

"We've got a tidal wave of corruption today . . . and the public wants something done," says Fali Nariman, a former solicitor general of India. "That's where the Supreme Court, sword drawn, has come riding in on its white horse."

Few courts in the world have such sweeping powers. Article 142 of the Indian constitution empowers justices to pass any decree "necessary for doing complete justice." Article 144 compels all other authorities in India to aid the court, and Article 32 gives every Indian citizen the right to file suit in the Supreme Court to redress violations of fundamental rights, even if the complainant isn't a victim.

Wielding these powers, the justices have taken swipes at some of India's most intractable problems. Every other Friday, Justice Singh and a colleague order India's biggest polluters and derelict regulatory officials to appear before them. The hearings are part of a series of public-interest lawsuits aimed at compelling India's federal and state governments to enforce nominally tough environmental-protection laws. Several times, the justices, scornful of the government's conduct, have dispatched their own researchers to measure emission levels around the country.

Bypassing regulators, the court has established air-pollution standards for major cities and ordered new cars to use lead-free gas. The justices have also implemented a program for cleaning up the Ganges River, holy water to Hindus but now fetid from industrial and human waste. The court has closed hundreds of polluting factories. The justices are also trying to clean up the city of Agra, home of the Taj Mahal, where scientists say acid rain could crumble the massive white-domed monument in just 50 years.

"The Indian political system has collapsed," says M.C. Mehta, the lawyer who has filed many of the environmental suits and winner last month of a Goldman Environmental Prize, given to one person from each continent for environmental action. "Only the Supreme Court is functioning any more."

Judicial adventurism has its critics. Some experts, such as Nani Palkhivala, a constitutional lawyer and the senior counsel of corporate giant Tata Group Ltd., say the court, in trying to strengthen democracy, is weakening it. "We have reached a degree of degradation and corruption where the only way of preserving order is to govern this country through the [Supreme] Court," Mr. Palkhivala says. "But if judges can rule, why not dictators?"

Indeed, Parliament nearly shut down in February in protest over a district- court ruling in a corruption case that branded the legislature as happy "to sit at the feet of underworld dons." The remark was expunged from the court's record.

Similarly, after the Supreme Court expanded the bribery investigation this winter, an aid to Prime Minister Rao complained the court was "functioning like a Third Chamber" of Parliament. The populist justices, he said, spend too much time "commenting on the character of bureaucrats, instead of disposing of the huge backlog of cases."

In fact, Indian justice is extremely slow. With backlogs of some two million cases in the lower courts and more than 50,000 in the Supreme Court, lawsuits take years to be heard. Even in the best of legal climates, justice delayed is justice denied: Some foreign companies, in particular, still prefer the summary justice of China's Communist bosses to the glacial jurisprudence of India's courts. "We're reaching the saturation point," says Mr. Nariman, the former solicitor general. "The courts can not assume to run a government."

But they may have to try for a while. With the electorate badly splintered among many different parties, political analysts expect a continuation of divided governments with thin parliamentary majorities. That means more compromises, and even less political will for reform.

And as the nation shifts toward a market economy, Indians fear, many politicians won't want to let business opportunities slip from their hands. "With such huge financial stakes, the Supreme Court will have to ensure everything is transparent," says Kapil Sibal, head of the Supreme Court Bar Association.

For years, the judiciary looked the other way. Cowed by the political dominance of former prime ministers Indira and Rajiv Gandhi and their Congress (I) Party, the justices seldom challenged executive or parliamentary prerogatives, lawyers say. When they did, such as during the national state of emergency declared in the 1970s, Mrs. Gandhi retaliated by transferring errant judges and locking them out of promotions.

In 1993, the Supreme Court restored its independence in what may have been its most brazen, and important, ruling to date. Though the constitution explicitly gives the executive, in consultation with the judiciary, the right to appoint judges and Supreme Court justices, the court simply reversed that. Now the Supreme Court has the final word on all judicial appointments, and the job of chief justice is passed down among the justices on the basis of seniority. The mandatory retirement age for judges is 65.

"That's how their power grew," says Mr. Nariman. "The bench started appointing judges itself."

In Courtroom No. 2, Justice Singh is on to his next case: the government's allotment of 16 lucrative gas-station licenses to relatives of senior officials. The licenses were granted by India's Oil Selection Board from a discretionary quota meant for special categories of people, including victims of terrorism and natural disasters, and cases of extreme hardship.

"In which of these categories do sons of ministers fall?" Justice Singh asks the government's lawyer. "My lordship, most are unemployed youth," the lawyer says. "All the proper guidelines have been followed." Justice Singh laughs. "There is one golden principal in selections like this," the justice says, "that your duty and your interest must not clash."

That is the sort of thing H.D. Shourie, a retired civil servant who filed this case, has been saying for years. Founder of a non-profit group called Common Cause (unrelated to the U.S. group), Mr. Shourie, 84, has submitted more than a dozen public-interest lawsuits to the Supreme Court, with impressive results.

After striking Calcutta lawyers closed local courts to protest a colleague's battering by his client, Mr. Shourie persuaded the Supreme Court to bar all strikes by lawyers. His evidence of rampant mishandling of India's blood supply prompted the court to require licensing of blood banks and to outlaw pay-for- blood. And a Shourie lawsuit led to the court's eviction of some 4,000 unqualified residents of government-owned compounds in New Delhi, including a former minister and his herd of cattle.

The gas-station licenses came up in a petition seeking the appointment of a national ombudsman. Arguing the case in court, Mr. Shourie presented a newspaper report about the nepotism at the oil board. From there, the excited Justice Singh now frames a whole new case. He instructs the lawyers to submit memos to him on why government agencies should be allowed to have discretionary quotas at all. "The state's largess can not be extended arbitrarily," he says. "Is there this type of quota in any other democracy in the world?" Then, he is off on a new tangent. "What we read in the newspapers every day . . . leaves a very bad taste as far as the functioning of democracy is concerned," he says. "We are lacking in many commodities in this country, but one of them is certainly intellectual integrity."

The court's activism, several justices have said, is needed to offset the failures of India's executive and legislative branches. The public's rising frustration leaves the court "with little choice but to act," said Chief Justice A.M. Ahmadi, in a lecture in February. Once the court's "corrective" measures are no longer necessary, the chief justice assured, the court's "aggressive role" will cease.