INDIA'S UNITY IS CELEBRATED AMID STRAINS
NEW DELHI, Jan. 26— As usual, elephants in billowing satin blankets carried children who had won awards for heroism. Helicopters flew by, showering the delighted crowd with marigold and rose petals. Tribal dancers marched to the music of bells and drums.
Hundreds of thousands of people lined the streets here today as military bands in scarlet uniforms paraded by. Tanks with huge guns were followed by rocket launchers and missiles. A caravan of camels wearing brass anklets carried men in white tunics and red turbans holding semiautomatic rifles.
But at the annual Republic Day parade in the Indian capital, there were also signs that the national unity being celebrated was being tested as never before. Security was tighter than it has ever been, according to people who have been coming to the parade for years.
In the past, for example, the Indian President has arrived in an open horse- drawn carriage to take his place at the reviewing stand. This year, President Zail Singh drove up in a six-door bulletproof Mercedes-Benz limousine.
In another departure from tradition, the tanks did not turn the barrels of their huge guns toward the reviewing stand, where Mr. Singh sat with Prime Minister Rajiv Gandhi and other dignitaries. Instead, the tanks raised and then dipped their guns straight ahead as they rumbled past.
In addition, every person in the huge crowd was frisked or made to walk through a metal detector before the parade.
The security was a sign of the uneasiness that has lingered after the assassination Oct. 31 of Prime Minister Indira Gandhi by gunmen identified as Sikh members of her bodyguard. Her shooting touched off riots and other violence, much of it directed at Sikhs by Hindus enraged over Mrs. Gandhi's death.
Many veterans of the Republic Day parade said they observed far fewer Sikhs than usual at today's event. By all accounts, hostility between Sikhs and Hindus remains corrosive months after the rioting ended.
President Singh, a Sikh, is a former Chief Minister of Punjab, where a Sikh- led separatist movement has been suppressed by the Indian Army.
Because he is an ally of Mr. Gandhi, Mr. Singh has been under particular attack from Sikh leaders who feel he has betrayed their cause. This apparently accounted for the especially tight security around him.
In an address to the nation on the eve of Republic Day, Mr. Singh appealed for an end to the ''scourge'' of sectarian violence. ''This country belongs to all of us, irrespective of religion, language, color or creed,'' he said, ''and we are all its proud citizens.''
Festivities Throughout India
Throughout the country, there were parades and festivities to commemorate the day 35 years ago on which India adopted a Constitution establishing itself as a republic. Traditionally Republic Day is India's biggest day of national celebration.
In Bhopal, where a chemical gas leak led to more than 2,000 deaths in December, floats and marching bands moved through the streets. In other cities and states, governors and ministers spoke of the need for national unity.
But many people at the parade in New Delhi said the mood was somewhat subdued. Brij Mohan, a 26-year- old factory worker who rode for four hours on a bus to the capital Friday, said the parade was less boisterous than the last one he attended in 1980.
Many also came to catch a first glimpse of the 40-year-old Prime Minister, who scored a huge election victory last month. ''I like him because he's young and a leader of young people,'' said Ratnakar Shet, a 30-year-old teacher from Goa. ''I think he will do anything for us.''
Mr. Gandhi, who was thrust into his post after the death of his mother, sat quietly at the reviewing stand today. But he burst into smiles and applause whenever a group of children marched by. He and Mr. Singh sat with one of the guests at the parade, President Raul Alfonsin of Argentina.
An Array of Contrasts
The parade had a dizzying array of contrasts. Early on, a military helicopter flew by decorated as an elephant, with stubby legs dangling and a big trunk stretched out in front.
There were several floats with national heroes, including India's first astronaut and the first Indian woman to climb Mount Everest. Elephants and camels mixed with rockets and radar equipment.
One float contained a tableau featuring a model of a Hindu temple and a huge hydroelectric plant. Another was shaped like a barge with a prow sculpted in the form of a bird.
Hours after the parade ended, the streets of New Delhi were empty. But at nightfall, one spectacular part of the celebration remained visible: the glow from Rashtrapati Bhavan, the huge sandstone presidential palace, lit by thousands of tiny light bulbs tracing the edges of the building. In the mist of the evening, the glimmer of the lights seemed to cast a spell over the city.