MAHENDRAGARH, India — This is what family planning in India often looks like: Women in their 20s, mostly farmers’ wives, gather at dawn on the stairs of a district hospital. Hours later, a surgeon arrives. His time is short. He asks the women to sit in a row on the floor of the operating room and then, in operations lasting a few minutes apiece, uses a laparoscope to sever their fallopian tubes, ensuring they will never again bear a child.

For decades, India has relied on female sterilization as its primary mode of contraception, funding about four million tubal ligations every year, more than any other country. This year, the government of Prime Minister Narendra Modi will take a major step toward modernizing that system, introducing injectable contraceptives free of charge in government facilities. The World Health Organization recommends their use without restriction for women of childbearing age.

New birth control options have long been advocated by international organizations, among them the United States Agency for International Development and the Bill and Melinda Gates Foundation. They say Indian women — often worn out, anemic and at higher risk of death because they bear children young and often — urgently need methods to delay or space pregnancies.

The number of lives touched by such policies is enormous and growing. India will soon surpass China as the world’s most populous nation, and by 2050 it is expected to gain 400 million new citizens, more than the population of the United States.