Processing of agricultural produce retains essential character and therefore qualifies for agricultural notification exemptions. Processing of agricultural produce for or on behalf of a client that does not alter the produce's essential character falls within the expression 'in relation to agriculture' in notification 14/2004 ST. Threshing and drying of tobacco (with packing) and processing of raw cashew to recover kernel, when provided as client processing business auxiliary services, are covered by that notification. Similarly, business auxiliary services by commission agents abroad to promote export of rice are covered by notification 13/2003 ST because rice is listed as agricultural produce.