China appears reluctant to accept Japan's offer of technical assistance to help its neighbor cope with a deepening air pollution problem, Environment Minister Nobuteru Ishihara said Saturday.

Japanese and Chinese government officials agreed in a Feb. 22 meeting in Beijing to promote technical cooperation and seek measures against PM2.5 particulates, which measure less than 2.5 thousandths of a millimeter in diameter but can cause severe health problems.

In a speech in the city of Tokushima, Ishihara said Tokyo had hoped the envisaged collaboration would serve as leverage in attempts to improve bilateral ties soured by the territorial clash over the Senkaku Islands. However, he said Beijing has not shown any enthusiasm about advancing the agreement.

Tokyo has offered to provide free instruments to record PM2.5 levels and to also send Japanese experts over to China, but Beijing has said it will dispatch researchers to the United States and Europe to gain expertise in dealing with air pollution, according to Ishihara.

The thick toxic smog enveloping parts of China has begun to drift across to Japan in recent weeks.