Wary about the spike in sugar prices in recent months, the prime minister's office has instructed the food ministry to ask states to impose stock limit, keep vigil on traders to ensure they don't make a killing and that retail prices are held below Rs 40 a kg.

The price of loose sugar has increased by Rs 3 to Rs 10 per kg in the past four months.While in most cities the sweetener was selling at Rs 40 per kg, in certain cities it has crossed this mark. Last October the average price was around Rs 30 per kg.

Sources said the Union food ministry is writing to state government to impose stock limit on sugar that the wholesalers and retailers can keep with them at any given point of time.

“The states are being asked to crack down on hoarders. It's observed that the gap between the ex-mill price and retail price is increasing and this indicates how traders are making more profit,“ an official said.