If the project was implemented, then it could have been beneficial for everyone. Pakistan is thinking that they should not proceed with the project because India will benefit from cheap gas. On the other hand, India thinks that it needs to deprive Pakistan from billions of USD worth of transit fees. And in the end both the countries will suffer from shortage of gas and funds. And Iran becomes the collateral casualty, as they can't export their gas to anyone. Some of the private firms from India were interested, but in the end they decided that the potential risk was too high.