Complex sentence: They are considered to be an untouchable group, outside the Hindu ritual ranking system known as varna, but, as with many untouchable communities, they too practise untouchability in relationships with other low-status castes.
Split into simpler sentences: They are considered to be an untouchable group, outside the Hindu ritual ranking system known as varna. As with many untouchable communities, they too practise untouchability in relationships with other low-status castes.