Service bond

Sir, I am currently working in a PSU. I have joined this PSU in July 2014 and as per my Appointment Letter it is written that "Employee is not allowed to apply for any outside position for 2 years.In case if employee quits the organization within a period of 2 years since the date of joining an amount of Rs 25000 is payable by employee to the organization ". As such I have executed a bond of Rs 25000 as per which if I quit the organization within a period of 2yrs I would be liable to pay a sum of Rs 25000. Now my query is that can an employer debar an employee for applying for any outside vacancies. Recently I had applied for a senior position with another PSU and forwarded a copy of my application through proper channel to my employer but in response to my application I got a response from my employer that as per terms of my appointment letter I am not eligible for applying outside vacancies. Also please clarify me if there is any exemption to employees for applying to UPSC advertised vacancies including Civil Services. Thanks & Regards, Rakesh Ranjan