BANGALORE - For four weeks, Mr Balappa has woken up anxious about how to feed his children. "I spend most of my day searching for rice. I can't look my wife in the eye anymore," the construction worker said.

Mr Balappa is stuck in a Bangalore construction site with 20 other families who came from Gulbarga, a neighbouring district, to work. When India imposed a nationwide lockdown on March 24, they tried to walk home, but the police beat them back. On Day 3, they ran out of rice and lentils, their staple food.

Without work, the daily wage earners are unable to buy food regularly. Volunteers sometimes give them cooked food, but Mr Balappa's wife Malamma said: "Charity keeps us alive, but is neither reliable nor enough to go around."

Millions of Indians could be on the brink of starvation, warn food policy experts. Independent researchers estimate that there have been at least 11 cases of people who died of hunger in the month since the lockdown. And these are only the deaths that have been reported.

A study which interviewed over 11,000 Indian migrant workers found that over half of them had food supplies for less than one day, and nearly three in four said they would run out of food in two days.

India is not short of food. Its food-grain godowns, run by the Food Corporation of India, are required to have a buffer stock of about 22 million tonnes to guarantee food security. Today, there is over three times that amount - 77 million tonnes - which could rise to 107 million tonnes after the spring harvest.

The surplus is so large that the government announced on Monday that some excess grain would be converted into ethanol for hand sanitisers. Yet, this grain is not feeding the hungriest.

Mr Jean Dreze, a development economist who has worked on poverty in India for decades, wrote in the Indian Express: "How would you feel if a family were to let its weakest members starve, even as the house's granary is full to the brim? That is what is happening in India today."

India's National Food Security Act requires 5kg of subsidised food-grain be given every month to poor families, who make up 75 per cent of the rural population, and 50 per cent of the urban population.

Following the announcement of a nationwide lockdown last month, the Indian government said it would provide another 5kg of food-grain and 1kg of pulses free for three months to about 800 million people identified as being in poverty. Some states promised to provide more grain.

On the ground though, much of the food rations have not reached their intended recipients. In many regions, food ration shops are giving less than the stipulated amounts, or turning people away for lack of IDs or because there's no grain left.

Economists and activists also say more than 100 million Indians entitled to cheap grain may be excluded, as the government's count of who is eligible for subsidised food-grain is based on outdated census figures.

Many others may be left out because they have not managed to obtain a ration card.

The tribal state of Jharkhand, for instance, has pending ration card applications from 700,000 households.

When Mr Balappa asked Bangalore authorities about the promised food-grain kits, officials demanded to see his government-issued ration card.

"My ration card is in the village with my father. Why can't they just give all people rations? Only the desperate will line up for it anyway," said Mr Balappa.

Mr Rajendran Narayanan, a volunteer with the Stranded Workers Action Network, said: "The woefully inadequate measures offer additional grains only to those who are already covered under the food security law.

"Most migrant workers don't carry their card with them. It's imperative that rations are universalised," added Mr Rajendran, who teaches at the Azim Premji University.

Mr Amartya Sen and Mr Abhijit Banerjee, India's two Nobel-winning economists, and Mr Raghuram Rajan, a former governor of India's central bank, wrote in The Indian Express last week that the country must provide temporary ration cards for six months to anyone who wants one.

"Giving away some of the existing stock, at a time of national emergency, makes perfect sense; any sensible public accounting system should not portray it as inordinately costly," they said.

Ms Dipa Sinha, the national convenor of the Right to Food campaign, said: "Food security is the best way to ensure we are able to bounce back. It has a multiplier effect on employment and health."

However, Food Minister Ramvilas Paswan warned that making the public distribution system universal would be "akin to opening a Pandora's box".

In an interview, he said the fault was not his, and instead blamed state governments for not providing enough ration cards to poor people. He said they were free to buy grain from the centre at a subsidised price and distribute it.

But India's 29 states are cash strapped. With a large part of the states' share in federal taxes still due to be transferred and expected tax collections hit under the restrictions, states are now cutting salaries and crowdsourcing funds.