New Delhi: Illegal mining in the face of falling groundwater levels and non-implementation of environment rules is posing a huge problem for the NCR. After Gurgaon, where groundwater levels have considerably gone down, it's now Faridabad district where mining activity is gaining momentum. A Faridabad based NGO, Shakti Vahini, has decided to oppose the Haryana government's decision to permit four new mines to come up in the area. According to group members, the two existing mines have not been following any environment rules, carrying out plantations, dust management or air pollution control methods.