Explanation:

Lack of load

Deccan plateau is eastward sloping i.e Western coast is elevated compared to eastern coast.Hence, there is no ground available for delta formation at Wastern ghat.
Most of the Western flowing rivers originate in Western ghat, now if they travel toward Western coast then they have to travel lesser distance than eastern flowing rivers before getting into the sea. On way to Wastern coast throgh hard rocks and over higher gradient, they couldn't collect large amount of Slit and flow with very high speed compare to East flowing rivers.
Hard Rocks of Western ghat don't allow Western flowing rivers to widen their mouth into sea, so these rivers form Estuaries whereas Eastern rivers flow through broken hills and mountain ranges. So, they are widened and flow with lesser velocity before entering into sea. So, they deposite sediments and silt before entering into sea and can form a Delta.