Indonesia yesterday set up roadblocks to screen for Covid-19 among travellers returning from the Hari Raya Aidilfitri holidays, as fears rose that mass gatherings and virus variants could trigger a surge of new cases in the world's fourth most populous nation.

Each year millions of Indonesians fan out across the sprawling archipelago after Ramadan to celebrate Aidilfitri and visit extended families, in a tradition known as "mudik"...