Losses could be losses from speculation, short term capital losses, losses from business income (if you're into trading F&O). The treatment of each of these losses in the Income tax vary. A detailed explanation is given in this blog on Z-Connect. http://zerodha.com/z-connect/traders-zone/taxation-for-traders/taxation-simplified
However if you have specific questions, you may post here or directly on Z-Connect
Thanks Venu Madhav, very informative article.