Recently India and Afghanistan set up an air freight corridor to by pass Pakistan's presence over their mutual trade. Why they need to do so, if they are sharing borders. What is the exact role of Pakistan and now why it is creating problem in trade?
Typically, air cargo is rather different than train/truck/ship cargo. Air transport is expensive, so air cargo is usually restricted to valuable or perishable goods that need to be moved quickly.
Take a look at "the common frontier":
Goes through those little hills called the Himalayas, through a region with few roads, and the few roads there seem to have one lane for each direction at most.
Gets into Afghanistan through the "panhandle" at its extreme NE border, forcing to a very long detour.
In relation with the above, in the map it seems as if there is not any road going directly from India to Afghanistan.
Goes through a "hot" spot like Jammu & Kashmir, which has been the place for a lot of infighting.