"While the trade-in policy has unlocked domestic demand potential, it has also accelerated the saturation of the secondhand market, creating new opportunities for emerging business models such as cross-border exports of used products," she said.

Wang agreed. "Promoting the export of secondhand mobile phones can alleviate China from its disposal burden, unlock idle resources and increase revenue," he said.

He noted the potential of such exports in contributing to the domestic and international endeavor to reach carbon neutrality.

By extending the lifespan of mobile devices and reducing resource consumption and environmental pollution, the use of secondhand phones can significantly improve resource efficiency, he said.

Quoting an estimate from Paris-based telecom company Orange, formerly known as France Telecom, Wang said reuse is a powerful driver for promoting green consumption and a crucial pathway toward green and low-carbon transformation.

The estimate shows that, compared to new products, the recycling of secondhand products can reduce carbon emissions by 90 percent.

Wang said there is a huge demand for secondhand phones from the international market.

"Driven by targets in carbon reduction, the European market is rapidly shaping a new landscape for secondhand electronics consumption," he said.

Orange, for instance, has set goals to cut emissions by 45 percent by 2030 and to reach net-zero emissions by 2040. To realize the goals, the company is aggressively expanding its refurbished cellphone business, aiming to source 10 percent of its total sales from secondhand devices this year.

This means that Orange alone will create an annual demand for over a million high-quality refurbished cellphones. "As global climate action intensifies, such demand is expected to grow further," Wang said.

He also noted the massive demand for secondhand cellphones in Southeast Asia and Africa.

"Consumers in these areas prioritize cost-effective communication devices to meet basic needs. China's refurbished cellphones, with their functional reliability and competitive pricing, perfectly align with the requirements in these markets," Wang said.

Some developed economies such as Europe, the United States and Japan have introduced policies to support the export of secondhand mobile phones, he said. The US, for example, has developed guidelines for the export of secondhand equipment to systematically address export challenges.

The International Data Corporation has estimated that worldwide shipments of used smartphones, including officially refurbished and used smartphones, reached 309.4 million units in 2023, up by 9.5 percent from 2022.

It projects that used smartphone shipments will reach 431.1 million units in 2027, with a compound annual growth rate of 8.8 percent from 2022 to 2027.