Wikepedia gives a very good
definition of trhe word chamaras follows,
"Chamar ("tanner"; from the Sanskrit Charmakara) is a prominent occupational caste in
India and Nepal. Chamar is a Dalit
sub-caste mainly found in the northern states, such as Punjab, Haryana, Himachal Pradesh, Uttar Pradesh, Bihar, Baluch and in Nepal at least north to the Himalayas. The traditional occupation of this caste was processing, manufacturing and trading in leather and leather goods. Most of the Chamars have now given up the leather related
work. Agriculture is also their most important occupation in which they engaged either in their full ownership or on share cropping basis in which they get
1/4rth, 1/3rd or
one half of the farm produce depending upon their agreement with the land owner."