The families of the 22 Indian diamond traders from Gujarat who have been held in a Chinese detention centre for almost two years on smuggling charges, without being sentenced, have appealed to Gujarat Chief Minister Narendra Modi to raise their case when he begins his official visit to China here on Wednesday.

The traders were detained in the southern port city of Shenzhen on January 8, 2010, accused of smuggling diamonds and evading up to $ 7.3 million in duties. They have been held in a detention centre since, and have not yet been sentenced for the alleged crimes.

In September, authorities ordered supplementary investigations into the case, leaving their families with an uncertain wait. Many of the families have since left China and moved back to Surat, where many of the traders come from.

Officials at the Indian Consulate in Guangzhou have been visiting the traders, while some of the family members were allowed to meet them in October.

Some of the family members and representatives of trading groups in Surat called on Mr. Modi before his China visit, and asked the Gujarat Chief Minister to raise the case in his talks with Chinese officials.

Mr. Modi will meet officials from the Communist Party of China’s International Department in Beijing. On Wednesday, he will also host an investment meeting for Chinese companies looking to invest in Gujarat.

It remains unclear if Mr. Modi will raise the case, and what impact his doing so could have. The case is being handled by the Ministry of External Affairs, whose officials have raised the issue with their counterparts in the Chinese Foreign Ministry on a number of occasions.

Indian officials have been wary of pressing Chinese authorities too hard on the case, citing a number of other cases involving foreign citizens where pressure appeared to backfire with heavy sentences being handed down.

But with 22 months having passed without a sentence being given, and investigations, as of last month, still continuing, some family members have called on the Chinese authorities for more clarity on the case.

“We have often been left with no information for months on end,” said one family member. “The uncertainty and complete lack of information, both about the case and how they are doing, has been the most difficult part in all of this.”

Some family members have also said they were willing to pay the necessary fines, and have called on the Chinese government to take an understanding view considering none of them had a criminal record and the status of their health. Many of the traders are Jains and vegetarians, with some suffering from health problems in the detention centre.

The Chinese Foreign Ministry in Beijing told The Hindu in a statement in September, issued in response to questions over the status of the case, that the Middle People’s Court in Shenzhen was “handling the case in accordance with the law”, and had kept Indian officials updated with the development of the case and arranged visits for officials.

"We ensure suspects’ rights to appeal, and have taken care of them in terms of their religious beliefs, culture and dining habits in a humanitarian spirit,” the statement said.