"Will a lockdown happen again?"

Over a grainy video call last week from a grotty little room in the western Indian city of Mumbai, the Sethi brothers repeatedly asked me this question, their voices trembling in nervousness.

More than a decade ago, Santosh and Tunna Sethi left their families and homes in the eastern state of Orissa, also called Odisha, in search of work. They arrived in Mumbai, more than 1,600km (994 miles) away.

Here, the brothers toiled in the shadows of the city's imposing skyscrapers that migrant workers build for the affluent. Ferrying cement, sand, bricks and stones, they earned 450 rupees ($6; £4.35) every day for eight hours of work. They lived, ate and slept in unfinished buildings, and sent most of their savings home to support their families.

Of India's more than 450 million migrants, 60 million are inter-state "labour" migrants, according to Chinmay Tumbe, the author of India Moving: A History of Migration. These workers are the backbone of the booming informal economies of India's cities. Despite contributing 10% to India's GDP, they are "socially and politically vulnerable", says Prof Tumbe.

Back in Mumbai, fear had gripped the Sethi brothers again.

"Will we have to return home? Do you have any information?" they asked.

With more than three million reported Covid-19 infections, the state of Maharashtra, which has Mumbai as its capital, is the stubborn epicentre of India's second wave of infections. The government has been warning of a full lockdown unless cases begin to fall.

On Tuesday it imposed stringent new restrictions to curb the virus spread, with only essential travel and services allowed until the end of April. Also, construction activity will be allowed where workers - like the Sethis - live on the site.

India's sweeping and badly-planned lockdown last year had forced more than 10 million migrant workers to flee the big cities they worked in.

The bedraggled men and women had left on foot, on cycles, on supply trucks and later in trains. More than 900 of them died on their way home, including 96 who died in trains. The exodus was reminiscent of the flight of millions of refugees during India's bloody partition in 1947. Harsh Mander, a human rights activist, called it "probably the greatest humanitarian crisis" that many Indians had seen in their lifetime.

Now Mumbai was being ravaged by the virus again, and the brothers were on the edge. Memories of the lockdown last year were haunting them. The suspension of work and transport had left them stranded in the city for two months last year, and they had ended up begging for food.

"It was a really bad experience. A strange time it was," Santosh Sethi, 43, said.

The two were part of a group of 17 workers who lived at a construction site in Mumbai. When the lockdown was announced on 24 March last year, they found themselves stuck without much food and money. Their contractor gave them just 1,000 rupees, but it was not enough to sustain their food needs for more than a week.

Stepping outside was risky because the police were beating up people on the roads for breaking lockdown rules. On video calls from their worried families, they broke down. Hunger was the "biggest problem".

"We would be hungry a lot of the time. We ate once a day. The battle for food was intense," said Tunna Sethi, 40.

Scrounging for food, the brothers met people involved with a non-profit group providing meals to the migrants and homeless. Eventually Khaana Chahiye (Food Wanted) served 600,000 migrant workers like the Sethis, and supplied more than 4.5 million meals to the needy in Mumbai during last year's lockdown.

"They were coming and telling us they would die in the city and never see their families again. The Sethis came to us looking for food and wanting to return home," said Sujata Sawant, a social worker, who met the brothers when they were desperate last year.

Ms Sawant and her fellow workers prepared kits for the workers which contained rice, lentils, oil, soap, spices, sugar, tea and salt to help them return to their abandoned work sites, have proper baths and cook food on their kerosene stoves.

Across the city, Ms Sawant said, employers and their contractors had switched off their phones and abandoned the workers. One worker turned up looking for soap, saying he had been bathing for 20 days without using one. Another said he was not able to access a public toilet for three days because he did not have the money to access a paid facility in his slum. Social workers say they found local politicians putting their images on food packets supplied by non-profits, pilfering rations to sell on the black market and often refusing to distribute in areas where they believed people did not vote for them.

The politics of hunger had hobbled efforts. "We found people were being often discriminated on the basis of religion, gender, caste, and language while distributing food during the lockdown," Neeraj Shetye of Khaana Chahiye told me.

Two months after struggling in Mumbai, the Sethi brothers were sent home in a plane chartered by a group of lawyers to send stranded workers home. They reached the airport in Bhubaneswar, Odisha's capital, at 8am. For the next five hours, they found no food or transport to take them home to Ganjam, 140km away.

"The officials treated us like dogs. They threw some biscuit packets at us, saying you have come from a place of disease," Tunna Sethi said.

Late in the evening they reached Ganjam, where they met their families after a 14-day quarantine in a school. The government gave them 2,000 rupees to help them restart their lives. But the money soon ran out.

Five brothers shared the family's one-acre plot, so all the food they grew went into family kitchens. For a few months, Santosh Sethi laboured on a neighbour's farm for 350 rupees a day. Some of the other returnees worked on government road works and a jobs guarantee programme to earn a living. Months went by like this.

In January their contractor called. The pandemic appeared to be easing off, cases were falling and work was resuming at construction sites. The brothers took a packed train to make a two-day journey to Mumbai.

This time their workplace was a block of 16-storey unfinished apartments on the outskirts of the city. One contractor still owes them some wages from last year. Anyway, there was no increase in per day rates. The brothers didn't have much of a choice, and began working.

They started sending money to their families: over the years, their earnings had paid for their children's private school fees, parents' medicines, a small concrete home with an asbestos roof.

I asked them if they felt as helpless as last year with fresh restrictions looming large. The train and bus stations in Mumbai had begun to fill up with panicky workers, trying to return home.

"Nobody cares for us. Can you help me get my pending wages from my contractor?" Tunna Sethi asked me. "I am a diabetic, I need to buy medicines. I have more expenses than my brother."

Santosh Sethi chimed in. Theirs is a world full of anxieties and uncertainties. And fear of hunger looms large.

"We are scared. Nothing like last year will happen again, right? If it does, you have to help us return home."