NEW DELHI - When Mohammed Faisal Khan perished in a fire that killed 43 workers sleeping in a small factory in New Delhi on Sunday his parents back in the impoverished eastern state of Bihar lost their eldest son and the family's sole breadwinner.

A victim of the Indian capital's deadliest fire in two decades, Khan was one of eight migrant workers from Narayanpur village whose charred bodies were found in the doomed leather processing factory.

"My husband is too unwell to work and my son was our only hope. We're completely shattered," Rubina Khatoon, his mother, told Reuters by telephone from the family home.

A neighbour, who died alongside him, had helped Khan get the job. Like thousands of migrant workers swarming Delhi, the victims earned as little as $2 to $3 a day.

Khan, 23, was using the pittance he made to support his sister and brother's education and buy medicine for his father, a diabetic, his mother said. "My son would have only two meals a day to save money and send 3,500-4,000 rupees ($49-56) to us every month. He would hardly keep 500-1,000 rupees for his day-to-day expenses," she recounted.

Too poor to afford rent, the victims ate and slept in a windowless room in the middle of plastic and leather processing machines. When the fire broke out, they died of asphyxiation before the flames swept through what became their death chamber.

Factories like the decrepit four-storey building where Khan and his co-workers lost their lives are a common sight in Delhi's narrow crammed back lanes.

They often operate without proper government permissions and with little or no regard for fire safety regulations.

This week, it was work as usual in the other industrial units along the lane where Sunday's tragedy occurred. The power for their machines delivered by a tangled electrical cables strung overhead.

"Look at that tangle of wires," said Ram Kishore Yadav, a labourer, staring up from the street where 42 men died.

"I won't be surprised if another fire breaks out around here." ($1 = 71.7700 rupees)

(Reporting by Mayank Bhardwaj; Editing by Simon Cameron-Moore) ((mayank.bhardwaj@thomsonreuters.com; +91-11-4954 8030; Twitter: @MayankBhardwaj9; Reuters Messaging: mayank.bhardwaj.thomsonreuters.com@reuters.net))