European-style afternoon tea is becoming increasingly popular in China, where people also brew foreign black teas to have a break. [Photo provided to China Daily]

Xiao compares the tea market to that of fruit: "China produces a great variety, but we still want to eat imported fruit, as long as the fruit is good."

At first, her customers knew little about the foreign black teas, and were skeptical. Chinese people said the tea is too coarse and crushed, lacking the delicate appearance they liked in their own country's teas.

Since then, however, black tea from the two South Asian countries has been steadily winning new fans, with many flavors that are distinct from Chinese tea, Xiao says. Tea grown in different areas, soils and climates naturally differ in quality and flavor; some producers in the region even add spices.

There are more than 80 tea plantations in the Darjeeling area, and the number exceeds 2,000 in Assam, Xiao says of India.

Xiao's company has recently opened a teahouse named Darjeeling Black Tea Room in Beijing, which serves black tea drinks made with famous varieties from around the world. Occasional tasting events help tea lovers explore a range of flavors.

Wu Mi is the owner of Boarding Mountain, one of the largest distributors of Lankan and Indian black tea in Beijing. She speaks highly of the tea auction-to-trade system in the two countries, which she says helps keep the quality of tea products high.

Wu is from Fujian province, where some of the best Chinese black tea is produced, but she says most of her company's revenue comes from selling Indian and Lankan tea.

The company's creative blends of black tea used to be popular gifts, especially before 2014, but Wu now targets customers who buy tea for themselves.

Boarding Mountain has also opened three teahouses to offer customers an exquisite afternoon tea experience in Beijing, because European-style afternoon tea is often associated with black tea from India and Sri Lanka.