can anybody tell me how to get rid of these unwanted emails on my yahoo email? I usually get 15-25 emails on daily basis. main headings are

winner, lottery, ATM card, loan for further studies etc.

and one thing important is this that I used my email very vastly on internet, but now I have shrinked my usage of net and I have also unsubscribed from most of websites/forums etc. still i am the target of these spams. kindly help me.