A travel bubble between Hong Kong and Singapore due to open next week has been postponed for a second time, officials said on Monday, after a spike in cases in Singapore derailed the plan for quarantine-free travel between the financial hubs. The bubble was initially slated to begin in November 2020, but was called off after a rise in cases in Hong Kong. <a href="https://www.thenationalnews.com/lifestyle/travel/hong-kong-and-singapore-to-start-quarantine-free-travel-bubble-next-month-1.1211854">It was announced in April</a> that the delayed plan would start from May 26. Under the plan, travellers would have to test negative for Covid-19 before departure and on arrival to move freely between the cities. Hong Kong and Singapore have been largely successful in keeping the virus at bay over the past year with strict border controls and effective tracing of infections but new cases in Singapore in May have dashed hopes for the air travel bubble. "In light of the recent increase in unlinked community cases, Singapore is unable to meet the criteria to start the Singapore-Hong Kong ATB [air travel bubble]," Singapore's Ministry of Transport said. But both sides remained committed to launching the bubble safely, it said. The Hong Kong government said another announcement would come on or before Sunday, June 13. Singapore announced on Friday its strictest curbs on social gatherings and public activities for months owing to a rise in community infections in recent days. Hong Kong's daily cases have dropped to low single digits while the government has relaxed some coronavirus rules for vaccinated people in a move to incentivise residents to get inoculated. The travel bubble was due to start with one flight a day into each city, with up to 200 travellers on each flight. Officials had said that if the seven-day moving average of the daily number of unlinked local Covid-19 cases was more than five for either Singapore or Hong Kong, the scheme would be suspended. For Hong Kong, which has banned non-residents coming to the city since March 2020, the deal with Singapore would have been its first travel link with another city. Cathay Pacific and Singapore Airlines were due to be the airlines offering the initial flights.