Uphill battle

Uphill battle - something very difficult because other people are causing problems for you.

Example - "Environmentalists face an uphill battle convincing people to use their cars less."

Image - http://i.nextmedia.com.au/Utils/ImageResizer.ashx?n=http%3A%2F%2Fi.nextmedia.com.au%2FNews%2Fuphill_challenge_boulder_shutterstock.jpg&w=480&c=0&s=1