The Unesco World Heritage Committee is “concerned” about the state of the Wadden Sea and will discuss the issue at its 46th annual meeting in New Delhi this week.

The committee has gathered in India to determine which world heritage sites should be added to the list and which should be listed as being in danger. Last year, Unesco warned it was concerned about plans to extract gas from under the sea, saying the move threatens biodiversity.

The Wadden Sea – an area of islands, sea and mud flats stretching from the Netherlands to Denmark – won inclusion on Unesco’s list of world heritage sites in 2009.

A new Unesco investigation into the environmentally-sensitive area has found the situation is currently not serious enough to warrant threatened status. Nevertheless, the report notes, there may be”potential cumulative impacts” from numerous activities and infrastructure developments.

These, the committee says, include oil, salt and gas extraction, ports and shipping, and energy facilities, which “could be exacerbated by climate change, especially through accelerating sea level rise”.

The report’s findings will be discussed by delegates on Thursday.

In March, the then-mines minister Hans Vijlbrief blocked plans to extract gas from underneath the Wadden Sea after it emerged the sea levels are rising faster than previously forecast.

Gas company NAM had hoped to start drilling off the north coast of Friesland to compensate for the closure of the Groningen gas field, which triggered thousands of earthquakes and destabilised buildings in the northern province.

Parliament had already voted against granting NAM a licence to open a drill site in the village of Ternaard and a majority of people in Friesland opposed the plan in last year’s provincial elections.