Sikh-Hindu clash tests Mr. Gandhi; Violent backlash could build pressure for independent Sikh nation

''I will go anywhere. I don't want to stay in India,'' the old Sikh said Sunday, tears rolling down his cheeks as he sat in a makeshift camp near Delhi. It was the first time since the assassination of Indira Gandhi on Wednesday that India's capital was fairly calm.

The reported death toll in India stands at 1,000 - half in New Delhi - and could be as high as 1,500, according to authoritative accounts.

Last week's four days of communal violence were the worst that India has seen since the strife that accompanied the subcontinent's partition 37 years ago, as frenzied mobs of largely illiterate, unemployed Hindu youth sought revenge for the murder of Indira Gandhi by two Sikh members of her elite security guard.

Only on Saturday evening, following his mother's cremation and amid rising national protest, did the new prime minister, Rajiv Gandhi, begin taking stern measures to bring the situation under control.

Some 5,000 Army troops fanned out through the capital. Armored personnel carriers took up position in east Delhi's neighborhood of Trans-Yamuna, just across the Yamuna River from some of the capital's most elegant villas and residential parks; 350 Sikhs are feared to have been slaughtered in Trans-Yamuna alone.

A curfew was reimposed in New Delhi, and on Sunday night 100 towns and cities remained under curfew - with 30 of them under patrol by steel-helmeted, battle-ready military troops.

Outside the refugee camp in Trilokpuri where the old Sikh sat, armored personnel carriers lumbered by, patrolling this conjested neighborhood - a swarming mass of government housing projects and dilapidated slums - which was the scene of 40 hours of anti-Sikh mayhem on Friday and Saturday, before the security forces finally intervened.

Beyond were the remains of charred buildings: eerily deserted gullies and alleys, a child's twisted, burned bicycle, and a defaced picture of the Sikh guru, Gobind Singh. Thousands of rampaging Hindu youth had stormed through settlements in Trans-Yamuna.

Bringing a semblance of control to the country is clearly Rajiv Gandhi's most pressing task.

As the security forces in the capital came under mounting criticism for their failure to act, Mr. Gandhi reinforced security by two appointments, naming the former home secretary, M.M.K. Wali, as the lieutenant governor of New Delhi, and transferring the chief of the paramilitary border security force to the home ministry of the central government.

At a press conference, shortly after his swearing in Sunday, Mr. Wali gave a clean chit to the Delhi police, saying ''They did their jobs excellently to curb violence.... There will be no scapegoats.''

He put the official death toll in the capital at 458, and said that 20,000 homeless were now in makeshift refugee camps. Expressing confidence that, by this evening, ''everything would be under control,'' Wali acknowledged that the four days of mayhem were ''the most harrowing experience that Delhi has ever had.''

Nearly all of the 100 chiefs of state and government, foreign ministers, and members of the world's royalty left New Delhi as quickly as possible after Mrs. Gandhi's funeral Saturday afternoon. As the stately procession, to the salute of bugles and military guard, wound its way through the city and the remarkably small crowds (estimated at 100,000), it was perhaps the greatest tribute to the dynamic, aristocratic former premier that her body was accompanied by a large number of dignitaries from both East and West.

Yet as the procession reached the cremation grounds on the banks of the Yamuna River, midway between the samadhis - or monuments to the dead - of her father and Mohandas Gandhi, smoke obscured the sky from across the river in the Trans-Yamuna colonies.

The old, homeless Sikh from Trilokpuri who will go ''anywhere'' is an immediate test for Rajiv Gandhi, as are India's 15 million Sikhs, and the ongoing voltatility in the strategically important state of Punjab.

After the Indian Army's assault in June on the Sikh's holy Golden Temple, bitterness and anguish among Sikhs swelled. The moderates among their leaders became radicalized. Ever larger numbers joined the extremist underground.

And the ghastly savagery provoked against them, in four vengeful days, is precisely what the late militant leader Sant Jarnail Singh Bhindranwale had hoped would occur.

His strategy was to bring the Sikhs throughout India - those he called the ''diaspora'' - into the Punjab, where Sikhs constitute 52 percent of the population today, and thus change the demographic balance. This is also precisely what proponents of ''Khalistan,'' that visionary Sikh nation, also wanted to occur. Sikhs constitute less than 2 percent of India's 700 million people.

If Mr. Gandhi does not move deftly and quickly to open a door to the Sikhs, the concept of Khalistan can only gain sway. Many observers in New Delhi already say it may be too late.