A curfew was imposed on May 9 after deadly clashes forced Mahinda Rajapaksa to resign.
His brother Gotabaya has left Rajapaksa to rule as president.
Many government and private buildings flew multi-colored Buddhist flags, while residents visited all the white-clad temples for the Sunday festival, commemorating the Buddha’s birth, enlightenment and death.
The more than a month-long predominantly peaceful anti-government protest turned violent earlier this week when supporters of the former prime minister stormed a protest camp in Colombo, set fire to tents and beat protesters. Clashes, and retaliation against government officials, have killed at least nine people and injured more than 300 others.
New Prime Minister Vikram Singh, who has led the country five times before, appointed his first cabinet on Saturday.
As the sole legislator of his United National Party in the country’s parliament, he has relied on the support of Sri Lankan Podujana Peramuna of Rajapaksa to form the government.
Saturday’s four cabinet appointments, all of which were from Rajapaksa’s party, failed to satisfy protesters seeking to remove the family from the country’s politics.
Due to the epidemic, rising oil prices and the government’s populist tax cuts in Rajapaksa, Sri Lanka is in the worst economic crisis since independence in 1948, with massive inflation and a shortage of fuel and other necessities.