India posted a 38.8-percent drop on the year in polished diamond exports in September to almost US$1.51 billion, according to provisional trade data published by the Gems & Jewellery Export Promotion Council (GJEPC).

For the 2012 fiscal year to date, the country's exports of polished diamonds plummeted 41 percent to US$13.29 billion

In the polished diamond imports category, the GJEPC said they dropped 72.3 percent to US$371 million last month.

For the April-September period, polished imports dropped 79.9 percent to US$1.85 billion.

Meanwhile, imports of rough diamonds jumped 44.1 percent to US$1.349 billion in September, but were down almost 13 percent on the year to US$7.0 billion for the fiscal year so far.

As for rough exports, they edged down 1.34 percent to US$157.8 million last month. For the April-September period, rough exports amounted to US$746.1 million, down 13.7 percent on the year-earlier period.