CALCUTTA.-- "We will have to go through hell to meet the situation" Prime Minister Indira Gandhi told the Indian Parliament last week. She spoke, during a debate, about the 6 million frightened Bengali refugees who have fled into India to escape Pakistani military repression in East Pakistan. The refugees will have to go through hell, too.

They have, in fact, passed through several levels of it already the terror campaign of the army, the long days of walking to India with little food and often-polluted water, and, at the end of the trek, a cholera epidemic. Well over 5,000 cholera cases have been counted among the refugees. The epidemic is still taking refugees lives, though it is under some semblance of control. Now other afflictions are starting to take their toll - malnutrition, typhoid, dysentery, pneumonia. And the monsoon rains have begun to make life even more desperate for the 2 minion refugees who are living in the open because there is no room in the camps.

India, width her limited resources, has been trying to provide for this pitiful army of displaced persons: but there is no way to keep up with the influx, for tens of thousands continue to stream across the border every day. And Indians in the congested border areas - they were originally sympathetic to the refugees and to the Bengali independence movement that the Pakistani Army is trying to crush - are turning resentful. Refugee consumption has forced food prices up, and cheap refugee labor has forced wage rates down.

Perhaps the Government's greatest fear today is an outbreak of Hindu-Moslem bloodshed, a periodic blight on the subcontinent since 1947, when British India was partitioned into predominantly Moslem Pakistan and predominantly waves of Hindu India. While the early waves of Bengali refugees were fairly equally divided between Hindus and Moslems, nearly all the recent arrivals have been Hindus.

Government officials are afraid that chauvinistic Hindus might seek revenge on India's Moslem minority of 60 million. Extra police are being sent to the tense border states, which have sizeable Moslem pockets. The main worry is unstable West Bengal, an already overcrowded, violence-prone state that has received the bulk of the refugees - over 4 million of them.

New Delhi is now trying to move the refugees from the border states to less crowded regions, but other states do not want them and are unlikely to take a significant number, regardless of central government prodding .

DESPERATE MOVES

The refugees do not want to move, either. They want to stay as close as they can to their native land - and preferably in West Bengal, whose people share their Bengali language and culture. In some cases, desperate Indian officials have cut off the refugees' rations to induce them to board trains for camps in the interior. The cost to India in social disruption cannot yet be measured, for, despite all fears of cataclysm, the situation so far has been reasonably well controlled and violence has been sporadic and minor.

But the economic cost is tangible and staggering. If the refugee flow stopped today and if it cost only one rupee (13 cents) a day to support each refugee - both unrealistic assumptions - the bill for one year would be nearly $300-million.

A country whose 550 million people enjoy an average income of only $80 a year clearly cannot bear such a burden without disastrous results.

But foreign help - so quick and so generous after last year's natural disaster in East Pakistan, the cyclone -has been sluggish in reacting to this man-made disaster. Only about $50-million in aid has been pledged so far, including American and Soviet airlifts that began moving small numbers of refugees out of crowded border areas last week. Most of it came only after the dramatic headlines about the cholera epidemic.

The problem, however, cannot be solved in India, no matter how lavish the foreign aid. The ulcer lies in East Pakistan, and the still-heavy flow of refugees confirms - as do independent reports from inside East Pakistan - that the army's program is continuing there.

The Pakistani Government's amnesty appeal to the refugees to return to East Pakistan "and take part in national reconstruction" has evoked bitter laughter from the displaced Bengalis, Only a few thousand refugees, all In northern Meghalaya state, have crossed back into East Pakistan - not out of confidence in the Government's offer but because of the hostility of the Meghalaya tribal people.

The Western powers, notably the United States and Britain, keep repeating - without direct criticism of Pakistan - their desire for a "peaceful political accommodation But they cannot suggest a political solution that would be viable without the Awami League, the now-banned party whose autonomy movement is the target of the army's offensive .

OFFICIALS IRATE

A week ago, the United States "counseled restraint" on both India and Pakistan "because of the possibility that the situation in East Pakistan and eastern India could escalate dangerously.''

Indian officials and private citizens alike were irate. Last Tuesday, Foreign Minister Swaran Singh - in Washington as part of a tour of major world capitals to present India's case - remarked with irritation on a television interview show: "What are we asked to restrain ourselves about? What is India expected to do?" The Americans backed off two days later, with the State Department saying that the United States "welcomed the restraint which India has shown."

Washington, in urging restraint, apparently had in mind the recent statements by Mrs. Gandhi and other Indian officials that if the world community did not pressure Pakistan into stopping its killing in East Pakistan and into creating secure conditions for the refugees' return, "we shall be constrained to take all measures as may be necessary to ensure our own security."

WAR NOT IMPOSSIBLE

That India eventually might go to war with Pakistan to keep its social and economic fabric from disintegrating cannot be ruled out Although no war preparations or planning are visible, and diplomats here do not believe that another such war is imminent, talk of it is nevertheless growing

Politicians are pushing the Government dally to take a harder line, and newspapers argue that war would be a lot cheaper than caring for the refugees (pointing out that the war with Pakistan in 1965 cost less than $70- million ) .

One high military source, while stressing that war would be "a last, desperate resort," added: "No country is going to go under without a fight. India certainly can't afford to spend $1.3-million a day on refugees. Our economic situation would deteriorate to such an extent that there could be a revolution in India. We couldn't carry on."