In 2007, the Indian press reported that India did not want to develop a full-range ICBM in order to avoid the risk that international sanctions on its ballistic programme would be tightened.
I don’t think India would be slapped with international sanctions if it did develop an ICBM; I doubt Europe and the US view India as a potential threat, in the same vein they did Libya/Iraq or still do for Iran and North Korea. If anything, I’m sure the US and some parts of Europe are quietly pleased and would encourage India to develop more sophisticated nuclear delivery systems, primarily as a bulwark against Chinese military expansion in Southeast Asia.
The fact is that, although India clearly has the means to develop an ICBM, it doesn’t really need to as it’s main potential threats come from Pakistan and China.