NEW DELHI.-The frightened refugees pouring into India from East Pakistan have posed for New Delhi a problem perhaps as serious as any it has faced since independence In 1947.

According to Indian figures, the number of Bengalis who have crossed over to escape the Pakistan Army-which since March 25 has been trying to crush the Bengali independence movement in East Pakistan-has Sopped three million. Tens of thousands more arrive every day- pitiful, dazed, broken people carrying a few salvaged belongings. Some are wounded. Others have died on the way.

They are now massed, like a human chain. in schools, public buildings and open fields along India's 1350-mile border with East Pakistan. India is trying to provide adequate shelter and care, but camps of tents or bamboo- and-thatch barracks cannot be erected fast enough to keep up with the flow. Schools have been shut down to house some of the refugees, but these cannot be kept closed indefinitely.

CHOLERA THREAT

Sanitary facilities are inadequate, adding to an already severe health problem. Indian hospitals are overflowing with the wounded and sick, many of whom have to lie on mats in the corridors and aisles. Dysentery is rife. Cholera and smallpox have broken out. And much of this is taking place in difficult-to-reach border regions- Assam, Meghalaya and Tripura-where medical care In normal times is either Inadequate or nonexistent. The problem of getting enough food to these remote areas is also straining India's limited resources.

And in the one easily accessible area, West Bengal state, the refugee influx has caused food shortages and forced prices up. At the same time, refugees offering to work in the fields at any price have driven the dally wage rate down. Resentment among local poor Indians has already surfaced, and in an overcrowded tinderbox state like West Bengal, one quarter of whose 45 million population is of earlier refugee origin, this could be explosive.

Hindu-Moslem tensions are also feared. Over-all, the refugee breakdown is 60 percent Hindu and 40 percent Moslem. Though Moslems predominate in East Pakistan, the Pakistan Army appears to be striking hard at the minority Hindus, who have always been regarded by the West Pakistanis as pro-Indian and who gave overwhelming support in last December's election to the autonomy- minded Awami League party, which has now been outlawed.

The Indians are worried, and not without cause. Prime Minister Indira Gandhi's Government feels that the Pakistanis are deliberately terrorizing Bengali Hindus and other potential dissidents into fleeing across the border to place grave strains on India's economic and social fabric. The Indians also fear that large numbers of Pakistani agents are crossing over, undetected, with the refugees. Further, New Delhi is concerned that the refugee camps might eventually become military staging areas for the independence struggle, thereby becoming a target for the Pakistan Army and turning the border into a battle arena.

As a result, India last week mounted a massive diplomatic and publicity campaign to try to mobilize world pressure against Pakistan. The Indian message being spread in world capitals is that unless other governments persuade Pakistan to halt Its "deliberate campaign of terror" and "deliberate expulsion" of Bengalis, India will be "forced to act to protect our national interests." What "forced to act" means Is not clear, and most diplomats here do not think India has actually mapped out in any detail what she will do if the world response is disappointing.

WORSE THAN CYCLONE

Though the civil war has caused more human disruption than the killer cyclone that struck East Pakistan last November, foreign governments have been far less responsive with relief. Within days of the cyclone, tens of millions of dollars in relief goods had been flown in, and much more had been pledged for long-range rehabilitation. The war refugees started flowing into India nearly two months ago and foreign aid still totals only a few million dollars. The cost of maintaining the refugees for just one year will run into the hundreds of millions, which India clearly cannot handle alone.

The apparent reason for the sluggish foreign response is that the United States and other Western nations were reluctant to give much aid unilaterally for the refugees, fearing that this might imply support for the Bengali independence movement and thus alienate the Pakistan Government-which has insisted that the civil war is entirely an internal matter and that most of the refugees are "Indian infiltrators" who have been routed by the Pakistan Army.

The Western nations were looking for an international relief effort, a less offensive conduit through which to channel their donations. The appeal last week by U Thant, United Nations Secretary General, "for humanitarian assistance . . . on an emergency basis" has presumably provided this umbrella. Yet even if the immediate relief problem is eased, and with it India's financial burden, the much more crucial question will remain-when will it be safe for the refugees to go home again?