An amendment to provide that if public improvements are assisted by certain funds under the Housing and Community Development Act of 1974 (section 106(d)), and if the improvements are required to comply with federal or state standards regarding water, sewage, air quality, or storm drainage, and if the costs are charged against property owned by low or moderate income people whose incomes exceed 50 per cent of the area's median income the funds received under section 106(d) are to be used to offset those charges so far as is practicable.