On 31st march 2016 a sum of ?15000 was still in arrears for subscription for the year ended 31st March 2015.It means

Dear Student
It Implies that the Amount of Rs 15000 is still not received for the year 2014-15 and in arrears with respect to the Subscription due amount. 
Same will be shown as asset in the balance sheet till it is not received.

Regards