The Centre has redefined the "active floodplain" of the Ganga and its tributaries and introduced regulatory and warning zones based on flood return periods.

The Jal Shakti Ministry, through a notification issued on August 7 and published in the Gazette on August 10, has amended the River Ganga (Rejuvenation, Protection and Management) Authorities Order, 2016.

The latest amendment removes the "construction free zone" wording and instead says that the banks of the Ganga and its tributaries and their floodplains shall be maintained to reduce pollution sources and pressures, and preserve their natural groundwater recharge functions through necessary measures.

At the same time, the Government has introduced a specific definition of "active floodplain", meaning an area of the Ganga or its tributaries coming under water due to floods corresponding to a one-in-five-year return period.

The amended definition of "flood plain" includes the active floodplain, a regulatory zone covering areas inundated between one-in-five-year and one-in-25-year floods, and a warning zone covering areas inundated between one-in-25-year and one-in-100-year floods.

Under the 2016 order, construction of permanent or temporary structures for residential, commercial, industrial or other purposes was prohibited in the Ganga, its banks, its tributaries and the active floodplain, subject to specified exceptions and permissions.

The 2026 amendment does not amend that provision, but defines the active floodplain as the area corresponding to a one-in-five-year flood.

The notification itself does not specify any construction permission or prohibition for the newly defined regulatory and warning zones.

The amended definition also includes areas of the Ganga or its tributaries that come under water on either side due to floods corresponding to their greatest flow or a flood with a frequency of once in 100 years.

The 2016 order had defined "flood plain" as the area of the Ganga or its tributaries that comes under water on either side due to floods corresponding to its greatest flow or a flood with a frequency of once in 100 years.

The latest amendment also substitutes the provision relating to maintenance of the river banks and floodplains. It says they shall be maintained to reduce pollution sources and pressures and preserve their natural groundwater recharge functions through necessary measures.

The order, called the River Ganga (Rejuvenation, Protection and Management) Authorities (Second Amendment) Order, 2026, came into force on the date of its publication in the official Gazette.

The principal order was notified on October 7, 2016, and was last amended on May 7, 2026, according to the notification.