If you read the first couple of pages of the prospectus, you will understand why the arbs "let" that happen
As of Oct. 26th, Barclays is no longer offering blocks of 50,000 shares at the Indicative Value for anyone who can cough up the money. This is because of the announcement from the Securities and Exchange Board of India of new policies affecting (adversely, for us) the ability of foreign investors to participate in the Indian stock market. I'd guess that Barclays is concerned that if they don't have the flexibility to invest in India that they need, they might find it financially inconvenient when people decide to redeem their shares of INP directly with Barclays. Barclays then announced, on Nov. 5th, that they would sell shares again, but only to the extent that other traders had already redeemed shares. In other words, no new shares of INP are being created. This eliminates (at east for now) the mechanism Barclays created for arbitrageurs tonaturally help keep the price of INP on the secondary market close to the Indicative Value. Right now, no one can buy shares cheaply from Barclays (at the IV) and then turn right around and sell them on the secondary market for an instant profit, thus driving the price there downward, back toward the IV.