Pressed by a lawsuit from environmentalists, the EPA yesterday said that smog clean-up plans are inadequate in nine of the nation’s most polluted urban areas, including New York City and Houston. EPA Administrator Carol Browner said that although the nine areas in question have made some progress, state governments still need to take additional steps to cut pollution. Six enviro groups filed suit this fall against the agency, charging that it had violated the 1990 Clean Air Act, which requires that the EPA write pollution-reduction plans for states that failed to write adequate plans of their own by 1994. Under a settlement filed on Tuesday, the EPA has agreed to write the plans if adequate ones are not approved within a year. Also, states that fail to meet federal smog guidelines and clean-up timetables by next May could lose money for highway projects. The other metro areas in question include Atlanta, Baltimore, Chicago, Hartford, Milwaukee, Philadelphia, and Washington, D.C.