With eight million shots in a day, India tries to energize its vaccination effort.

India administered 8.6 million doses of Covid vaccines on Monday, setting a national record on the first day of a new policy that offers free vaccines for all adults and aims to energize a lackluster inoculation effort.

Despite a slow start characterized by supply shortages and bickering between the states and central government, officials say that vaccine production and procurement are being accelerated to ensure that all of India’s roughly 950 million adults are fully vaccinated by the end of the year.

Monday’s total was the most Covid shots given in a single day in any country besides China, and the surge may have been partly because the vaccines were widely available and free for the first time to those younger than 45.

Local news reports have also suggested that Monday’s record may have been made possible by holding back vaccines in some states run by the governing party of Prime Minister Narendra Modi. In one state, Madhya Pradesh, the number of administered doses had shrunk to just 692 a day before the start of the new policy on Monday, when 1.6 million doses were suddenly administered.

And the boost was probably temporary — currently available supplies suggest that it would be difficult to sustain such a pace over the coming weeks. India has increased the availability of doses to 120 million this month, from about 75 million in May. About 135 million doses are expected to be available in July.

The inoculation drive relies almost entirely on two vaccines manufactured in India, and government officials have said that the companies behind those vaccines, the Serum Institute of India and Bharat Biotech, have promised to deliver a total of about 1.3 billion doses from August to the end of the year. The remaining doses are expected to come from other vaccines still under assessment or trial.

In India, a nation of about 1.4 billion people, the task ahead remains enormous. Although the country has administered nearly 290 million doses of vaccines so far, according to government data, less than 5 percent of the population is fully vaccinated. Less than 20 percent of people have received at least one dose.

The government has worked to iron out supply issues and ease online registration requirements that have hampered vaccine access, especially in parts of the country where smartphone and internet availability are spotty. Still, vaccine hesitancy — born of local superstitions, as well as misinformation spread by some political and religious leaders — persists, officials say.

The effort to ramp up vaccinations comes as the worst of India’s devastating second wave appears to be over, with most of India’s major cities easing restrictions and reopening the economy. India reported about 42,000 new cases on Monday, down from a peak of more than 400,000 in early May. The weekly test positivity rate has remained below 5 percent for two consecutive weeks, a sign that undetected cases in the population are also decreasing.

About 390,000 peopled have died of Covid in India, according to official figures, although experts believe that is a significant undercount. In recent weeks, Indian news outlets have published numerous reports of “excess deaths,” a figure that compares the average number of mortalities during normal times with the increased toll during the pandemic. The difference is often much higher than the Covid toll reported by the states, suggesting that the virus has claimed many more lives than the official statistics reflect.