Prime minister Dr Manmohan Singh today warned big business against operating price cartels, saying cartels were a crime and went against the grain of an open economy and had to be ended.

Speaking at an industry conference in the capital, Dr Singh said, it was unacceptable to obstruct the forces of competition from having freer play and that it was even more distressing in a country where the poor are severely affected by rising commodity prices.

"Profit maximisation should be within the bounds of decency and greed. If a liberalised economy were to succeed, business and government must give full play to competitive forces and the private sector should show some self-restraint," he said.

Immediately after the announcement of Union Budget 2007, cement manufacturers had defied the government''s attempts to temper prices of the higher-grade cements.

Singh also admonished business families and executives against excessive salaries and remunerations that fuelled the rich-poor divide, saying, "Rising income and wealth inequalities, if not matched by a corresponding rise of incomes across the nation, can lead to social unrest."

Rising economic growth over the last four years and easing of restrictions on imports had benefited the middle and wealthier English-speaking classes, without sufficient inclusive growth, or "reforms with a human face."