A glut of locally grown navel oranges is forcing retailers to slash prices to less than $2 a kilogram as citrus growers struggle to sell their biggest crop in 10 years.
Drenching summer rains and milder temperatures in the Sunraysia, Riverina and Riverland regions have produced the massive harvest - 70,000 tonnes more than last year, taking the haul to 250,000 tonnes. (based on the article in the Sunday Herald Sun)

Assuming oranges operate in a perfectly competitive market, use a well-labeled demand and supply model to describe how market equilibrium price of oranges is determined.