Complex sentence: A total of 512 people were arrested for various offences in the rally, far less than the 1,667 detained in the Bersih 2.0 rally the previous year.
Split into simpler sentences: A total of 512 people who took part in the rally were arrested for various offences. This is however much less than the 1,667 detained in the Bersih 2.0 rally the previous year.