At least 43 people were killed on Sunday after a massive fire broke out at a factory at Aanaj Mandi area in Delhi, according to an ANI report run by the Times of India.
50 people have been rescued from the building so far and more are still feared trapped inside.
Sources said 15 fire vehicles were immediately rushed to the site to douse the blaze.
A call about the fire was received at 5:22 AM following which 30 fire tenders were rushed to the spot.
Speaking to media, deputy fire chief officer Sunil Choudhary said: "A fire broke out in a 600 sq feet plot. It was very dark inside. It is a factory where school bags, bottles and other materials were kept." The fire has now been doused, he added.
Most of the people affected were labourers sleeping inside when the fire broke out.
Prime Minister Narendra Modi in a tweet expressed shock at the incident and said his thoughts are with those who lost their loved ones.
Delhi chief minister Arvind Kejriwal on Sunday described the fire incident in Delhi's Anaj Mandi area as "tragic" and said firemen were doing their best.
Delhi minister Imran Hussain said action will be taken against those responsible after a thorough investigation.