New Delhi, May 26: The online filing of applications for this year's civil services preliminary examination to select IAS and IPS officers has begun. This time the candidates will have the option to choose either the civil services or the Indian Forest Service or both, the Union Public Service Commission (UPSC) has said. Candidates who appeared in the civil services examination, 2011 but are otherwise ineligible for the examination this year due to completion of the number of attempts available, shall be permitted an additional attempt, it said in the recently issued notification for the prestigious test. The civil services examination is conducted by the UPSC annually in three stages-- preliminary, main and interview --to select candidates for prestigious Indian Administrative Service (IAS), Indian Foreign Service (IFS) and Indian Police Service (IPS), among others. This year, the preliminary examination will be held on August 23 in 71 centres at about 3,000 venues. Candidates are required to apply through online mode on the Commission's website--www.upsconline.nic.in. No other mode is allowed for submission of application. Filing of online applications started on May 23 and will conclude on June 19 (till 11.59 PM), according to the notification. Eligible candidates shall be issued an e-admission certificate three weeks before the commencement of the examination. The e-admission certificate will be made available in the UPSC website. No admission certificate will be sent by post, the UPSC said. Every candidate appearing at the examination who is otherwise eligible, shall be permitted six attempts at the examination, it said.