Notwithstanding the provisions of section 5 of chapter 40A of the General Laws or any other general or special law, rule, regulation, charter, ordinance or by-law to the contrary, during the governor’s March 10, 2020 declaration of state of emergency related to COVID-19 and for a period of thirty (30) days after the termination of the state of emergency, the board of selectmen or select board in a town having a town meeting form of government may, by a two-thirds vote of the full board, adopt zoning amendments to maintain compliance with the National Flood Insurance Program and to incorporate updated flood hazard areas as required by the Flood Insurance Rate Maps prepared by the Federal Emergency Management Agency.  Said action by the board of selectmen or select board may only be taken following a public hearing on said zoning amendments conducted by the planning board in accordance with the provisions of section 5 of chapter 40A of the General Laws, except as provided herein.  Any planning board hearing held or report with recommendation on such zoning amendments issued prior to March 10, 2020 shall satisfy the requirement for a public hearing and report hereunder. A planning board that has not held such public hearing must conduct said hearing within thirty (30) days of the effective date of this act, notice of the planning board hearing shall be posted on the town’s website in  addition to other methods of posting required by said section, and the report containing the recommendation of the planning board must be delivered to the board of selectmen or select board within ten (10) days following the hearing.  If no report with recommendation of the planning board is rendered within ten (10) days of the public hearing, the board of selectmen or select board may act on the zoning amendment. No zoning amendment acted unfavorably upon by the board of selectmen or select board shall be precluded from being considered by Town Meeting following the termination of the state of emergency.  The effective date of any zoning amendment adopted hereunder shall be the date of approval by the board of selectmen. Further, notwithstanding the provisions of section 32 of chapter 40 of the General Laws, the time for review by the attorney general shall be thirty days from the date of submittal of the by-law by the town clerk.