Complex sentence: Most of the rivers pour their waters into the Bay of Bengal; however, some of the rivers whose courses take them through the western part of the country and towards the east of the state of Himachal Pradesh empty into the Arabian Sea.
Split into simpler sentences: Most of the rivers pour their waters into the Bay of Bengal. Some of the rivers which lie in the western part of the country and towards the east of the state of Himachal Pradesh pour their waters into the Arabian Sea.