Historically, both Muslim countries and India have had some important intellectual achievements.  They have both also been home to important thinking in terms of religion and philosophy.

Both India and Muslim countries have had many religious thinkers who have been historically prominent.  India, for example, is the source of Buddhism, which has had a tremendous impact on the world.  This can certainly be seen as an intellectual achievement.  Similarly, Muslim countries have been the source of many thinkers on the subject of Islam.

Both were also the source of many mathematical and scientific achievements, with the Muslim countries perhaps being more prominent in this area.  India, of course, was the source of the idea of the zero and Indian thinkers were involved in the development of algebra.  Muslim countries were also the source of much development in mathematics (algebra and algorithm are both derived from Arabic words).  There were many important Muslim astronomers and thinkers (like Avicenna) in other sciences like medicine.

In short, both India and Muslim countries have been the sources of major intellectual achievements.