Centre redefines Ganga floodplain, drops 'construction-free zone' provision

The Centre has redrawn the definition of the Ganga’s floodplain, introducing separate regulatory and warning zones based on the frequency of floods while removing the earlier reference to a “construction free zone”.

The changes were notified by the Jal Shakti Ministry on August 7 and published in the Gazette on August 10 through the River Ganga (Rejuvenation, Protection and Management) Authorities (Second Amendment) Order, 2026.

Under the amended framework, an “active floodplain” is now defined as an area of the Ganga or its tributaries that is inundated during a flood corresponding to a one-in-five-year return period.


The broader definition of “flood plain” now includes three categories. These are 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.

The amendment also retains within the floodplain areas on either side of the Ganga and its tributaries that are inundated during floods corresponding to their greatest flow or a flood with a frequency of once in 100 years.

The earlier 2016 order had defined the floodplain as areas on either side of the river and its tributaries that come under water during floods corresponding to their greatest flow or a flood with a frequency of once in 100 years.

The latest notification also changes the language governing the maintenance of the river’s banks and floodplains. Instead of referring to a “construction free zone”, it states 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.

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

The 2026 amendment does not alter that construction provision. However, with the active floodplain now specifically linked to a one-in-five-year flood, it establishes the regulatory and warning zones as additional categories within the broader floodplain.

The notification does not separately specify whether construction will be permitted or prohibited in these newly defined regulatory and warning zones.

The amended order, which came into effect on the date of its publication in the official Gazette, is the second amendment to the River Ganga (Rejuvenation, Protection and Management) Authorities Order, 2016.

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