Source: www.delhimetro.net
The Delhi Metro Rail Corporation (DMRC) today said it would introduce some changes in its smart card add value and refund rules from May 21.

Therefore, increasing the minimum add value of the cards will help the commuters as they will not have to stand in queue and recharge their cards time and again, it said.
The initial minimum add value of the smart cards has been increased from existing Rs. 50 to Rs 100 (refundable security of Rs. 50 has been kept unchanged).
Subsequently, from the next transaction, the minimum add value will be of Rs 200 and further add values can be in multiples of Rs. 100 (like Rs. 200, 300, 400, upto Rs 1000).
In case of web top-up, the minimum add value amount will be Rs. 100 and multiple of Rs. 50, that is Rs. 100,150, 200, 250, upto Rs 1000).
About 12000 smart cards are refunded every day, of which 9% of smart cards are purchased and refunded on the same day. Similarly, around 30% smart cards are purchased and refunded within the same month. This has resulted in a pile-up of 9 lakh smart cards to be refurbished at a cost to DMRC. More info