Centre today said that it is working on a special index to fix wages under Mahatma Gandi National Rural Employment Guarantee Act. Talking to reporters in New Delhi, Rural Development Minister C P Joshi said that his ministry has sent a proposal to Planning Commission for consideration. He said according to the act there is no linkage between minimum wages of states and wages under the MGNREGA. He added that his ministry can not go beyond the provisions of the Act while fixing the wages.