KATHMANDU: Nepal Airlines Corporation (NAC) has urged all health institutions and laboratories — authorised by the government to conduct polymerase chain reaction (PCR) tests — to take caution as some of the passengers travelling to foreign destinations with negative PCR reports have tested positive for the novel coronavirus. NAC has appealed to the authorised health institutions and laboratories to carry out lab tests maintaining prescribed standards. At present, the national flag carrier has implemented rules according to which passengers have to produce negative PCR reports issued within 72 hours before taking the flight. Since a few passengers who boarded NAC flights showing negative PCR reports have tested positive for COVID-19 in Hong Kong, Dubai and Narita, the airlines has urged all to take caution. As a few passengers tested positive for coronavirus in foreign destinations, NAC's flights to some of the places have been banned resulting in financial loss and adverse impact in their reputation, the airlines said in a press statement. Moreover, all passengers will have to take their own responsibility if they tested positive for COVID-19 at foreign destinations.