All travellers landing in Dubai can be tested free of charge for Covid-19, according to the Dubai Health Authority. Nationals and returning residents will be given polymerase chain reaction (PCR) tests on landing in the emirate. Tourists have two options. They can take a PCR-test up to 96 hours before flying to the UAE and present Dubai authorities with the Covid-19 negative certificate. Otherwise, they can opt to undergo testing free of charge on landing in the city. Follow-up Covid-19 tests for any tourist exhibiting symptoms of the virus in-flight will also be conducted, even if the traveller has already obtained a negative certificate. The measures have been put in place by Dubai's Supreme Committee of Crisis and Disaster Management to help prevent the spread of coronavirus by air travel. All travellers arriving in Dubai must also fill out health declaration forms that disclose any possible symptoms of the disease. These will be given to passengers by the airline they are flying with. At Dubai airport, every passenger will have their temperature scanned via thermal screening devices and everyone must download the Covid-19 DXB app. Valid medical insurance is also needed for tourists. Those that arrive without it will be asked to sign a disclaimer undertaking that they will "bear all costs of quarantine and treatment". Any traveller testing positive for Covid-19 once in Dubai will have to undergo a 14-day quarantine period. This can be done at home if conditions comply with official guidelines from the Covid-19 Command and Control Centre. People who are home-sharing or live in high-density housing will have to be isolated at a separate facility. This should be provided by their employer or the government, with companies bearing the costs according to the Dubai Health Authority's most recent guidelines. Those flying into Dubai must also observe precautionary measures including wearing face masks, maintaining two-metre social distancing and washing their hands regularly.