As the days grow colder, Pasang has made preparations for the winter by purchasing a generous amount of natural gas to warm his home.

"In the past, we burned cattle dung for heating. The rooms would be covered with dust, and the sky would sometimes get gray," said Pasang, a resident of Lhasa, capital of southwest China's Tibet Autonomous Region. He just bought 1,000 yuan (about $157) of natural gas.

His home was connected by natural gas pipelines seven years ago. "With the gas, my home is warmer, and we are also contributing to bluer skies," he said.

Now, the signature azure skies dotted with white clouds not only give local people a breath of fresh air but are also a vital part of the region's magnetism for visitors from home and abroad.

In the first 10 months of 2021, the air quality of Lhasa ranked second among 168 major Chinese cities. The city has been among the top-10 for several consecutive years, said the country's Ministry of Ecology and Environment.

The wide use of natural gas is one of the keys behind the clean air in Tibet. In Lhasa's case, natural gas has been adopted for heating in more than 90 percent of its urban area, said a local company in charge of natural gas supplies.

Amid the country's boom of new energy vehicles (NEVs), Tibet is also popularizing NEVs while phasing out older cars with high pollution and energy consumption.

Early this year, the capital city added 76 new-energy buses to its fleet, and all intracity routes have made use of the clean vehicles.

Electric cars are also gaining popularity for their eco-friendly features and lower costs. Penpa, another resident in Lhasa, said he and many of his friends have replaced their traditional vehicles with electric ones.

"Everyone should play a part to keep the air clear in Lhasa," Penpa said.

In the first eight months, the proportion of days with good air quality was 99.1 percent in Tibet, said the regional department of ecology and environment.

Clear skies have added to the attractiveness of Tibet to tourists, as even a casual smartphone photo can look surreal with the blue skies and white clouds as the background.

The starry nights in Tibet are also more mesmerizing due to the crystal clear air. Over the past few years, the plateau region has become a dream destination for many sky gazers.

Atop a mountain over 5,000 meters above sea level, the Ali observatory -- more than 1,400 km from Lhasa -- is still frequented by astronomy lovers who brave a zigzagging road to get a closer look at the stars.

Zhou Yunhe, director of the observatory, said more than 3,100 tourists have visited the observatory since the turn of the year.

Despite the impact of COVID-19, Tibet received 36.89 million tourists in the first three quarters this year, up 15.2 percent year on year, and tourism revenue surged 26.6 percent, official data showed.

"We will toughen up measures to guard the blue sky in order to have clearer air, bluer skies and a more beautiful environment," said Norgyel, head of the regional department of ecology and environment.