NEW YORK, July 19 -- China and the United States have maintained a strong and robust sister city relationship that sustains bilateral trade and friendship, a former U.S. mayor has said.

"Being sister cities with other cities is a great way to develop the ties of friendship," Annise Parker, former mayor of Houston, told Xinhua in a recent interview. "The relationships we have with our sister cities in China are some of our strongest."

So far, Houston has had 18 sister cities around the world, including Shanghai and Shenzhen, Parker said. In terms of trade volume, China has been the second largest trading partner with Houston, the fourth largest U.S. city, only behind Mexico.

During the first five months of 2019, Houston exported to 202 countries and imported from 179. By May, China registered over 6.1 billion U.S. dollars in imports and exports with Houston, tantamount to 6.4 percent of the city's total trade with all its foreign trading partners, according to the latest statistics by the Greater Houston Partnership (GHP).

The GHP is an economic development organization serving over 1,000 member companies in the 11-county Houston region, including Austin, Brazoria and Chambers.

"Houston is a city that is committed to trade and commerce," Parker said, adding that it is also crucial to strengthen cultural and people-to-people ties between the two sides.

She pointed out that sports is an effective way to create new business and cultural relationships, as Chinese basketball superstar Yao Ming has been "the most amazing boost to our ability to meet new people in China."

Yao played for the Houston Rockets as a center from 2002 to 2011 and helped the team reach NBA playoffs four times.

"I led a trade mission to China. And we visited three cities while I was there. Everywhere you went, you could say Houston or Houston Rockets, and someone would say Yao Ming," the former mayor said.

In this aspect, Parker said that peer-to-peer exchanges help develop deeper understanding between the United States and China, as they go beyond business relationships to deeper personal relationships.

"You also dispel myths. You have the ability to bridge misunderstandings. You can create new synergies and new opportunities," she added.

Over the last 40 years, bilateral sister city relationships have flourished between China and the United States. The two countries now enjoy 277 pairs of sister relationships at different levels, and the momentum is still going strong.

"When you have a good alignment of the cities and the people on both sides, and people of good faith who are willing to work together, it benefits both. And it benefits not just the people who were involved in the sister city relationships. It opens up new avenues for the cities to cooperate in other ways," Parker said.

She noted that there has been a surprising amount of ancillary benefits brought by sister city ties, such as promoting educational and cultural exchanges.

"A school in one city and a school in another city will decide that they want to twin (under the sister city relations,)" Parker said. "And they'll have students there who will decide that they want to study at a university in one of those cities. "

"We'll also have art groups from Houston that will go to Shenzhen to perform or ... vice versa," she added. "So it keeps rippling. There are more and more ripples that go across the pond every time we drop the pebble in."