X, in a statement posted on Twitter earlier, Mumbai’s civic authorities said “high winds” caused the collapse and multiple agencies, including the police, fire and National Disaster Response Teams, were involved in the rescue operation.
Also, officials say that the hoarding was many times higher than the permissible size and the agency that put it up did not have permission.
The company was issued a notice and asked to remove the building and remove all similar hoardings from the city immediately.
Maharashtra Deputy Chief Minister Devendra Fadnavis said that the state government will provide financial assistance to 500,000 rupees ($5,987; £4,767) to the families of those killed and injured in the incident.
Monday’s dust storm brought parts of the city to a standstill, uprooted trees, caused travel chaos and power outages.
Several flights at the city’s international airport were temporarily grounded or diverted, local media reported.
Mumbai is one of the many cities in India prone to severe flooding and rain-related incidents during the monsoon season – which usually falls between June and September.
Additional reporting by Tom McArthur in London.