Eighteen months after an earthquake destroyed hundreds of historical sites across Nepal, the country has celebrated the restoration of the first major one, the Buddhist monument topped in gold that towers above Kathmandu.

One of the largest of its kind and a popular tourist attraction, the Boudhanath stupa was repaired, not with government funding, but with private donations from Buddhist groups and help from local volunteers.

The government has faced strong criticised for the slow pace of reconstruction across Nepal and its failure to repair the vast majority of the country’s heritage zones.

Boudhanath stupa on its reopening day after its renovation for earthquake damage. Photograph: Prakash Mathema/AFP/Getty Images

The Nepalese prime minister, Pushpa Kamal Dahal, praised the private restoration effort in a speech at the monument, and said it should serve as an example for the rest of the nation and was proof that Nepal could rebuild its heritage.

He added: “This example puts pressure on us in government to reconstruct all the houses and temples that have been damaged.”

Believed to have been built in the 14th century, Boudhanath was shaken by a magnitude 7.8 earthquake in April 2015 that killied almost 9,000 people and displaced millions. Its sprawling white stupa, topped with four pairs of hypnotic eyes that stare out across the capital was largely spared, but the gold spire that sits atop the dome was severely damaged.

Flowers are dropped from a helicopter. Photograph: Niranjan Shrestha/AP

Local and foreign donors contributed more than $2m (£1.6m), said Milan Bhujel, an adviser to the Boudhanath Area Development Committee, which helped organise the effort. Donors also gave 31kg of gold, which covers the structure’s pinnacle, including 13 steps that represent the Buddhist path to enlightenment.

The stupa is illuminated during a purification ritual. Photograph: Narayan/Pacific/Barcroft Images

Over the weekend, a helicopter showered Boudhanath with flowers during a three-day purification ceremony that drew thousands of pilgrims. The complex, which from above resembles the Buddhist diagram of the cosmos known as a mandala, was floodlit with festive blue, red, green and yellow lights.

Ratna Bazra Lama, a 63-year-old businessman who lives at the edge of the complex, said he was ecstatic to see the stupa’s pinnacle completed after watching it being taken apart and then left in scaffolds for months.

Pigeons rest on the Boudhanath stupa. Photograph: Navesh Chitrakar/Reuters

“I could see it from my window every day. It was so sad,” he said. “So we’re happy it’s been restored,” and fortunate too, since most other damaged cultural sites remain wrecked.