India, faced with a steadily rising population despite nearly doubling sterilizations in the last year and comparable increases in other modern birth control methods, is embarking on a crash program to develop a safe injectable contraceptive, according to health officials.

A task force has been formed within the Indian Council of Medical Research and given priority status to accelerate development of an antifertility vaccine, according to K.C. Kapoor, a family planning official in the Health and Welfare Ministry.

Health and Welfare Minister B. Shankaranand earlier had advised a parliamentary committee that the government of Prime Minister Indira Gandhi had committed itself to stepping up the immunological approach to birth control, but no details were disclosed.

The director of family planning for the Council of Medical Research, Dr. B.N. Saxena, said the government is "very much committed" to developing an indigenous antifertility vaccine. He said it has not considered introducing foreign-produced injectable contraceptives, like the controversial Depo-Provera, which has been linked to cancer-causing agents. Indian law prohibits the distribution of any drug that has not been approved in its country of origin.

"We have a long way to go. It will require many more studies before we can begin trials, but we are going ahead with a great deal of urgency," Saxena said in an interview. He estimated that preclinical antitoxicity studies and further tests to ascertain a consistant response could not be completed before the end of this decade.

Health and Welfare Ministry officials did not disclose the cost of the project, but Saxena noted that a recent study by Stanford University estimated that development of a safe injectable contraceptive would cost between $55 and $65 million.

Indian health officials pointed out that unapproved antifertility vaccines have been given to women in neighboring Bangladesh and Pakistan by international family planning agencies, but that neither country is developing an indigenous product.

Several leading Indian scientists, including the respected Dr. Pran G. Talwar of the All-India Medical Center, are already engaged in preliminary research on safe injectable contraceptives, and recently have made important breakthroughs, Saxena said.

The crash program was ordered amid rising concern in the Gandhi government that despite an enormous investment in family planning programs, India's population has doubled to nearly 800 million in the past 35 years and is expected to reach 1 billion before the end of this century.

It is estimated that only about 27 percent of the 120 million couples of childbearing age are protected by some modern method of contraception, and that if the birth rate is to be reduced to 21 per 1,000 from the current 33 per 1,000, then a minimum of 60 percent of the couples of childbearing age would have to use such contraceptives.

As time passes, even more couples would have to practice birth control to achieve the same results, and the government "would have to run to keep standing still," according to a recent report issued by the Family Planning Foundation of India, a major backer of the antifertility vaccine approach.

The foundation report said that if firm steps were not adopted to curb population growth, India would be faced with the prospect of having to consider far more stringent and unpalatable choices. It mentioned the example of China, where the one-child family concept is being strictly enforced.

The shift in birth control emphasis comes at a time when sterilizations performed in the fiscal year ending in March approached 4 million for a nearly 43 percent increase over the previous year.

It was the greatest increase since 1976-77, during the emergency era when the prime minister's son, Sanjay, allegedly ordered the forcible sterilization of thousands of males.

Last year's figures include tubal ligations and vasectomies, and were boosted, in part, by an increase in incentive compensation from 70 to 100 rupees (about $7 to $10), according to family planning experts.

Subsequently, the national target for sterilizations has been raised this year from 4.52 million to 5.9 million.

Insertion of intrauterine devices last year rose 43 percent to slightly more than a million, and the number of women using contraceptive pills rose nearly 44 percent to more than a million, according to Health Ministry officials.

Pill users continued to comprise the smallest proportion of protected women, with only 170,000 reported.

A Family Planning Foundation task force that studied birth control during the past year has proposed a package of incentive and disincentive schemes to bring down the birth rate. Shankaranand said state health officials had already been asked to implement some of the schemes.

They include financial incentives to communities that reduce their birth rate, and the issuance of "green cards" to families of no more than two children.

The cards would entitle a family to preferential treatment in hospitals, in getting electricity and water connections and admission to schools.

Disincentives proposed include denial of maternity leave to women who already have two children and low priority in housing assignments and government loans. Families with two children who accept sterilization would receive the equivalent of $50 and those accepting sterilization after three children would get $30.

The task force acknowledged that among poor families, children are economic assets, and said the strategy should be to end their economic exploitation as wage earners by providing adequate compensation to adults.

Rami Chabra, program director of the Family Planning Foundation, said that immunology alone would not curb India's population explosion but would have to be coupled with increased efforts to bring all forms of birth control to the poor.

But, Chabra said in an interview, "injectables would have a convincing appeal. People accept it against cholera and polio. That straightaway breaks a barrier."

She said she was encouraged by the new impetus given by the government to injectable contraceptives, and also by family planning's improved credibility after "falling into disrepute" during the 1975-77 emergency declared by Gandhi.