Besides, two other suspected cases one each from Bengaluru and Hyderabad also proved to be negative, as per the reports of the ICMR-NIV, Pune.
One of Mumbai patients has tested positive for Rhinovirus, one of the routine common cold virus.
Earlier, the two Mumbai cases were secluded in the BMC's Kasturba Hospital - which specialises in such diseases - after they were detected with possible symptoms following thermal screening of nearly 1,800 passengers coming from Chinese airports to the Chhatrapati Shivaji Maharaj International Airport since the past five days.
The duo had complained of cold-related symbols and mild cough and further medical tests were conducted on them, said an official.
The CSMIA medical teams have been advised to send travellers from China exhibiting any similar symptoms to the Kasturba Hospital for further medical protocols.
However, no passenger with a history of visiting China's Wuhan city in the past fortnight has been found positive during thermal screening for Coronavirus.
Besides setting up the seclusion ward in the hospital, the civic health authorities have also issued instructions to all private medicos in the city to inform the BMC in case they detect any signs of Coronavirus from their patients who have recently returned from a China trip.
As a precautionary measure, the CSMIA started thermal screenings of all inbound passengers in the pre-immigration area, arriving by Air China and RwandAir which operate flights between Mumbai and China, since January 19.
The city Health Department and state Health Ministry are closely monitoring the situation on a regular basis amid global reports of over two dozen deaths due to Coronavirus and more than 850 under treatment for the disease.
( With inputs from IANS )