Accumulation of Input Tax Credit happens when the tax paid on inputs is more than the output tax liability. Such accumulation will have to be carried over to the next financial year till such time as it can be utilised by the registered person for payment of output tax liability.
However, the GST Law permits refund of unutilised ITC in two scenarios, namely if such credit accumulation is on account of zero rated supplies or on account of inverted duty structure, subject to certain exceptions.