Free admission to top tourist venues, hotel rooms at half price, and cheaper flights have made the Tibet autonomous region a hot destination for tourists this winter, which is traditionally a quiet tourist season.

The region received 2.46 million visits from tourists from Nov 1 to March 15, an increase of 84.2 percent year-on-year, the region's Tourism Development Bureau said in a statement on Wednesday.

This has been the second winter that the regional government promoted its "travel to Tibet in winter" campaign to attract tourists. Between Nov 1 and March 15, people got free admission to top tourist sites, including Potala Palace－a UNESCO World Heritage Site－where admission during other periods will set visitors back 200 yuan ($29.70), and advance reservations are required during peak season. The winter campaign also requires all hotels in the region to offer rooms at half price, including five star hotels such as the Shangri-La in the regional capital of Lhasa.

The measures showed immediate results when they were introduced from February to April in 2018, said Go Khok, mayor of Lhasa. Compared with the 2016-17 winter season, the number of visits doubled from November 2017 to April 2018.

"Traditionally, tourism in Tibet only booms between May and October and then becomes very quiet in the winter, which has resulted in low rates of return on investments in tourist infrastructure," said the mayor.

This winter, the average occupancy rate of hotels in Lhasa reached 60 percent, and soared to 90 percent in some hotels. In the past, many hotels chose to send their staff to branches outside Tibet to cut costs in winter, but this season was quite different, he added.

About 130,000 people in the city make their living from tourism, and some 70 percent are local farmers and herdsmen. So the boost in tourism will significantly increase their incomes, Go Khok said.

Meanwhile, Tibet has stepped up efforts in environmental protection to cope with the increasing number of tourists, he said.

"The city's 13 districts and counties will be equipped with wastewater treatment plants by June 1. We must plan environmental protection measures ahead of tourist development," he said.

Siga, manager of Pingcuo Kangsang Hotel in Lhasa, had a very busy winter. The hotel, which offers rooms with a view of Potala Palace, was fully booked during the Spring Festival holiday in February.

What surprised her even more was that reservations kept coming in after the holiday, she said.

"Many small businesses such as restaurants normally decide to close down for the winter because business has typically slowed to a crawl. This year, they chose to stay open," said Siga, who was born in the city.

Some hotel quests even came to Tibet for weekend getaways because cheap flights from Chengdu, Sichuan province to Lhasa were offered over the winter, she said.

Although the region's climate in the winter months is relatively mild, there is a large temperature difference between day and night.

Also, people are more likely to suffer from altitude sickness in the winter when they travel to Tibet, which is located on the Qinghai-Tibet Plateau and has an average altitude of more than 4,000 meters, because there are fewer leafy trees pumping out oxygen in the cold months.

To attract tourists in the winter, many hotels including Pingcuo Kangsang have installed floor-heating systems in rooms. What's more, many hotel rooms are equipped with oxygen-generating machines to help people ease symptoms.