The fire was reported at 5:22 AM following which 30 fire tenders were rushed to the spot.
Chaotic scenes were witnesed at the site of the fire incident with relatives and locals rushing to the area.
According to a man whose three nephews were working at the factory, "At least 12-15 machines were installed in the unit. I have no idea about the factory owner.
"My nephews Mohammed Imran and Ikramuddin were inside the factory. I don't know their whereabouts," the distraught man said.
According to him, many units were operating from the premises which was located in a congested area.
Many people trapped inside were rescued and rushed to RML Hospital, LNJP and Hindu Rao Hospital, fire officials said. 34 people were brought dead to LNJP hospital and smoke inhalation was the primary cause of the death. Some of the bodies were charred, Dr Kishore Singh, Medical Superintendent, LNJP, said.
Out of the 15 injured brought to LNJP, nine people are under observation and others have partial injuries, he said.
Chief Minister Arvind Kejriwal described the fire incident as tragic and said firemen were doing their best.
"V v tragic news. Rescue operations going on. Firemen doing their best. Injured are being taken to hospitals," the chief minister said in a tweet.
PM Narendra Modi called the fire in Delhi's Anaj Mandi area is 'extremely horrific'.
My thoughts are with those who lost their loved ones. Wishing the injured a quick recovery, the prime minister said.