The Pakistan cement sector is likely to add 21Mt of additional capacity in the next four years, analysts said on January 5.   "We foresee the existing production capacity of the industry increasing by 20 per cent over the next 5 years," one analyst of KASB&Co said.  As such "We foresee at least 21Mt of additional cement capacity over the next four years." Among the cement manufacturers, Lucky is emerging as the market leader with the implementation of its massive expansion plans of 16,800 tonnes per day.   The expansion will help this particular company to gain pricing power as well as help it to exploit the growing demand of cement in the domestic as well as exports market. We have an underweight stance on the cement sector owing to the increasing demand supply gap in the industry.