Molar conductivity is defined as the conducting power of all the ions produced by dissolving one mole of an electrolyte in solution.
As dilution increases that is as the solution is further diluted, the concentration (molarity) of the solution decreases. The Iona move further away from each other and due to this there is less interactions between the oppositely charged ions of the electrolyte. Due to this the ions are free from any interionic interaction(interaction between the particles of electrolyte) and hence conduct more .