Two things actually. No.1, it is the public noises. It has got to do something with noise pollution. I am a bit scared when mentioning about them. I wouldn't be focusing on something at a time when noises come to me. No.2, my phone. When I am trying to concentrate on my study only, the phone calls from my friends is the thing that may distract me. Also, the social apps on it, that would distract me as well. So, that is it.