Chidambaram welcomed the decision to vaccinate all above the age of 18 years from May 1.

''However, we have to caution the government that this decision brings with it huge responsibilities,'' he tweeted.

The former minister said the first and foremost requirement was the availability of vaccines, adding that there were widespread complaints about the lack of supply of the jabs.

''The government's claim that there is no shortage of vaccines is hollow and untrue,'' he said.

''When the surge in demand happens on May 1 and more people flock to hospitals for vaccination, will there be adequate stocks of vaccines all over the country?'' he asked. ''If people are turned away at hospitals, there will be great resentment and protests.'' Chidambaram said the time to plan for May 1 started many weeks ago, wondering whether the government was prepared for it.

''I am sceptical. Nevertheless, I urge the government to start preparing NOW in order to meet the much greater demand for vaccines on and after May 1,'' the Congress leader said.

All adults will be eligible for coronavirus vaccination from May 1 after the government announced its liberalised vaccine policy. Currently, only people above 45 years of age are eligible to get the vaccine