The carrying capacity of any given population is determined by its

Limiting resource Carrying capacity : The suppoable population of an organism, given the food, habitat, water and other necessities available within an ecosystem is known as the ecosystem is known as the ecosystem's carrying capacity for that organism RRefers to the number of individuals who can be suppoed in a given area within natural resource limits, and without degrading the natural social, cultural and economic environment for present and future generations For human population more complex variables (Sanitation, medical care) are sometimes considered as pa of necessary infrastructure Below carrying capacity, population typically increase ; While above, they typically decrease May depend on a variety of factors including food availability ; water supply, environmental condition and living space Ref: internet (Wikipedia)