What is the fine-grained topic of the following text: ** The rupee fell to an all-time low of 171.60 per dollar on Wednesday, surpassing the previous low of 171.00 hit on Tuesday, due to foreign selling in government securities and exporter greenback sales, market sources said. Only return the topic.
The depreciation of the rupee to an all-time low due to foreign selling in government securities and exporter greenback sales.