Ion chamber sensitive to low energy pulsed X-rays has been developed for area monitoring at the electron accelerators Indus 1 and 2 of Raja Ramanna Centre for Advanced Technology, Indore. Conventional monitors available commercially underestimate the X-ray background because of pulsed nature of the radiation and are not sensitive to X-rays below 100 keY. For this purpose, a high pressure ion chamber made of aluminium with all welded construction has been developed and tested for use in pulsed X-ray background. The chamber has 25 litre sensitive volume, filled with nitrogen at 85 psi and current sensitivity is 12 nAIRIh. The chamber can measure exposure levels from 20μR/h ~ to 100 mR/h and has uniform energy response within ±12% from 35 keY to 1.25 MeV of X-ray energy. The ion chamber gave more than 86% collection efficiency at 100 mRJh average pulsed X-ray background for 500 V operating voltage. Theoretically evaluated collection efficiency values closely match with the experimentally observed values. The design details and characterisation of the ion chamber under different X-ray energy exposures and collection efficiency estimation for pulsed X-ray background have been studied.