Dear Prashant, the punishment of stoppage of three increments with cumulative effect means that he will not draw the next annual increment for a period of three years, and at the end of three years, he will draw the next increment. Let us assume a case where the punished employee was in the grade of Rs. 5000-100-6000 and was drawing a basic pay of Rs. 5500, with the increment due on 15th September every year. As the punishment of stoppage of increment with cumulative effect is imposed, his basic pay will remain static at Rs. 5500 on 15th September 2011, 15th September 2012, 15th September 2013, and up to 14th September 2014. On 15th September 2014, he will draw the next increment, and his basic pay would go up to Rs. 5600. Had it been without cumulative effect, his pay would be fixed at the stage where he would have been had he not been punished, i.e., he would be straight drawing Rs. 5900 on 15th September 2014 without going through the stages of Rs. 5600 to Rs. 5800. Thus, where the punishment is the stoppage of increments with a cumulative effect, the loss is enduring or lifelong, whereas where the punishment of stoppage of increments is without cumulative effect, the loss is short-term and does not make a difference in the long run.
Hope this clarifies.
Regards, KK