NEW DELHI, Aug. 22—The immediate effect of India's friendship treaty with the Soviet Union has been a significant cooling of the crisis atmosphere here, but the basic cause of the crisis—East Pakistan—remains unsettled, and many observers are still gloomy about the prospects of averting an India-Pakistan war.
"I'm still sticking by my feeling that the chances are about 50-50," one Western diplomat said yesterday.
Indian officials appear slightly more optimistic. "India will never start a war," one remarked, "and now the chances of our being attacked have been reduced."
The long-range problem, as several Western and Indian observers see it, is that India stands to lose almost as much from a freezing of the status quo as from a war. If war is the worst alternative, one source said, "a freeze with more refugees arriving from East Pakistan and no end to the crisis there is also unacceptable."
India continues to hope that international pressure on Pakistan, the guerrilla activities of the Mukti Bahini "freedom fighters," economic problems in Pakistan and deteriorating morale among Pakistani soldiers will force Islamabad to seek a political solution with the Bengalis of East Pakistan.
But while some if not all of those pressures are building to force Pakistan's hand, the Indian-Soviet treaty has not dissipated the forces propelling India toward more active intervention in the East Pakistan crisis. It is generally believed in Delhi that the Soviet Union, which now has more influence than other foreign powers here, is actively trying to restrain India from taking any inflammatory steps.
In addition, Indian officials say they expect Moscow to do all it can to counsel restraint in its talks with Pakistan. However, it is not clear what effect such counsel will have either here or in Islamabad.
One indicator would be if India reduced its military aid to the Mukti Bahini. But several Indian officials indicated last week that they expect the guerrillas' activities to increase, implying that there will be no cut in Indian support.
Moreover, despite Pakistan's claims that the guerrillas would collapse without Indian arms and training, most sources here and in Dacca are convinced that India cannot turn off the guerrillas completely, even if it wanted to, and that therefore the series of skirmishes and acts of sabotage in East Pakistan will continue whatever course Delhi follows.
Besides the economic cost of sheltering more than 7 million refugees and the political pressure from sizeable Indian groups which believe that war would ultimately be cheaper and a more successful end to the crisis than continuing to await internal change in Pakistan, Prime Minister Indira Gandhi's efforts to avoid war will face further problems if Pakistan executes the East Pakistani leader Sheikh Mujibur Rahman who is now being tried in secret on treason charges.

SHEIKH'S DEATH

Indian officials believe that the death of the Sheikh might force Delhi to take some action demonstrating its solidarity with the East Pakistanis.
The most likely step would be recognition of Bangla Desh, the exile government in Calcutta in whose name most Mukti Bahini guerrillas operate.
Delhi is fully aware that recognition would increase the likelihood of an all-out attack by Pakistan. At least, well-informed sources believe, it would sharply reduce Mrs. Gandhi's room for maneuver.
Pakistan would automatically break diplomatic relations and the guerrilla leaders' expectations of Indian support would soar. Delhi would find it difficult to resist stepping up its military aid to a government it recognized, and increased levels of fighting Pakistani leaders have threatened, would bring a Pakistani leaders attack on India.
Three beliefs are fundamental to India's view of the crisis. The government genuinely does not want war ; government leaders are convinced that Pakistan's two wings will never be peacefully reunited and India is determined that it cannot care for the refugees forever and they must return to their homes.
India therefore continues to hope, as it has almost from March 25 when the East Pakistan crisis began, that Pakistan will give up its effort to crush Bengali resistance in the east and that a government will be established there which will welcome the refugees back and want friendly relations with Delhi.
Indian officials talk of such a solution coming around the end of the year, when they believe the Pakistan will face discontent in the west because of the cost of the East Pakistan occupation and cutbacks in foreign aid. Non-Indian observers here generally believe that Pakistan can pursue its present policy much longer ; and both Indians and Westerners recognize that the desperate internal conditions which Dehli hopes will force Pakistan to a peaceful solution of its problems could also goad Pakistan's military government into a desperate effort to recoup through war with India.
When the two nations fought in 1965, the war lasted 10 days and both sides were close to, if not at, the point of military exhaustion when the ceasefire was called. If another war broke out, sources here believe, India would do better than 1965. It seems likely to well-informed observers that the Indian army could capture East Pakistan in about a month of fighting while fighting on the Western front would most likely be close to a repeat of the earlier bloody stalemate—at least initially.
Both sides are very short of oil, and without outside assistance their armies' mobility could cease very quickly once again. In addition, although India has a far larger defense industry, with over 30 factories to Pakistan's less than five, its air force could be quickly restrained by the Soviet Union, whose technicians handle a large share of maintenance and key production jobs.
The Indian army has about 900,000 men, but more than a third are tied down along the mountainous borders with China and could not be pulled out to fight Pakistan. According to sources here, Pakistan has about 400,000 men in its army.

AIR FORCES

The air forces of the two nations, observers believe would be likely to cripple each other in the initial days. Some Indian cities—Delhi and Bombay—and some Pakistan cities—Karachi and Lahore—would be likely bombing targets before the air war ended. In addition, both nations are extremely short of transport aircraft, which would further limit the ability of their armies to make rapid deployments.
If its petroleum supplies held out, India seems better able to fight a war for as long as one or two months, but sources here doubt that any war would last that long. As in 1965, the Soviet Union and Western powers would work together to stop the shooting, and it would he difficult for the side that was winning to resist pressures for a cease-fire.
The cost in lives, property and money would further impoverish two poor nations, and it seems unlikely that an international effort to move beyond a ceasefire to a treaty ending the war would be possible without some solution to the problem now existing in East Pakistan. India signed its 20-year friendship agreement with the Soviet Union to diminish the chance of such an inconclusive and costly war.
For the moment, the situation has been calmed, but not defused. No one here is confident he knows what the long term holds for India and Pakistan.