The East African Court of Justice has blocked the plans of the Tanzanian government to build a road through the north of the Serengeti national park.
The grounds for its injunction are that it would upset the migration of wildebeest between Tanzania and Kenya each year and would therefore violate the rules of the East African Community on conservation and the suitable use of natural resources.
The East African Court in Arusha is the judicial arm for the five-nation group of the East African Community made up of Burundi, Kenya, Rwanda, Tanzania and Uganda.
Nearly two million wildebeest and other animals, such as gazelle, zebra and eland, migrate across the borders between Tanzania and Kenya in search of grazing, depending on the rains.
The Tanzania government wanted the road across the north of the Serengeti to order to boost tourism and to connect poor communities in the west of the country on Lake Victoria with the more prosperous north and east.
An alternative project is now being considered south of the national park.