"We are happy that 12 diamond traders held in China returned to India late last night. We are making all efforts to bring back the remaining traders," Gems & Jewellery Export Promotion Council (GJEPC) Chairman Rajiv Jain told PTI here.

22 traders, hailing mostly from Gujarat and Mumbai were arrested in southern China's Shenzhen city and were charged with smuggling diamonds worth 50 million yuan ($7.3 million). They were accused of sourcing diamonds illegally from Hong Kong for sale in the Chinese market.

Shenzhen, known for its diamond processing units, is a city in China's Guangdong province close to Hong Kong.

On December 7 last year, the Shenzen Intermediate People's Court, which heard the traders' case, ordered their deportation while sentencing others for varied prison terms.

One detained Indian trader was released on bail with orders that he should stay in China as he was wanted in connection with the appeal petition filed by a Chinese citizen arrested in connection with the case. The other nine persons were sentenced to varied prison terms ranging from six years to three and half years.