"The blaze started on the 10th floor of the building, Sargam Society (G+16), located near Ganesh Garden in Tilak Nagar.
A large number of vehicles, including twelve autorickshaws, two taxis and two-wheelers, were completely gutted while two residential buildings also caught fire.
Pathak, the son of retired director general of police and former Pune police commissioner K K Pathak, was arrested on Saturday.
Fire brigade officials admitted that organisers of the event had not complied with nearly 10 fire safety measures.
The fire was brought under control after three hours, a Mumbai Fire Brigade official said, adding that cooling operations were underway.
Nine members of a family were among the deceased in the first incident which took place around 11.15 pm on Wednesday, when Mumbai experienced heavy rains throughout the day, at the New Collector Compound on Abdul Hamid Road in the Malwani area of suburban Malad, the officials said.
'All restaurants and pubs must treat the issue seriously and appoint safety officers. This chalta hai attitude cannot work.'
Safety instructions were neglected as LPG cylinders were brought by the organisers and kept under the stage of the Make in India event where a massive fire broke likely due to an electric spark coming into contact with combustible material, a probe into the incident in Mumbai has said.
The fire broke out in a flat on the 20th floor.
A fire broke out because of a suspected leakage in an oil pipeline passing through a land owned by the Mumbai Port Trust in Wadala in central Mumbai, but no one was injured.
As Mumbaities bids adieu to Lord Ganesha on the final day of the festival, Rediff's Hitesh Harisinghani and Satish Bordes speak to lifeguards of city's beaches.
A second submarine berthed near INS Sindhurakshak submarine that exploded and sank was saved from a possible disaster thanks to an alert senior Mumbai Fire Brigade officer who was near the mishap spot.
The building did not have the mandatory Occupation Certificate granted by the Brihanmumbai Municipal Corporation, but it was already occupied by around 58 flat owners, according to the civic body.
Fire brigade sources claim that apart from Indian Navy submarine INS Sindhurakshak, there were two other submarines at the naval dockyard at the time of fire on Tuesday night.
There have been more than 49,000 fire incidents in Mumbai in the last one decade, killing over 600 people, the Maharashtra government had told the assembly in November 2018.
An Indian Navy submarine caught fire after an explosion and sank in Mumbai late on Tuesday night, with 18 personnel on board, including three officers, feared dead.
'Unni swung up his MP5 and fired a burst across the atrium. The bullets hammered into the wall. Then he bounded up the stairs leading to the other set of doors opening into the Palm Lounge. It was a terribly risky move because he didn't have a buddy to cover him.'