Actually it depends on what you are downloading......
When I was at Penn State, USA. I used to download BitTorrent to download movies at my aprtment but one day I connected to Penn State WiFi network and my BitTorrent started to upload movie from that network. Security officers of Penn State send me an email about breaking law and took my interview regarding to that. So friends Torrent is not LEGAL!!! when you are downloading movie or softwares or music files.
But some companies want to share their information through Torrents then that torrents are LEGAL.