India\'s benchmark stock index completed its biggest weekly decline this year after the nation\'s factory output contracted in March, prompting concerns the country\'s economic growth is slowing. Maruti Suzuki India Ltd., the nation\'s biggest carmaker, sank to its lowest level in three months. Tata Power Co., the largest electricity generator outside state control, tumbled the most since December. The benchmark BSE India Sensitive Index, or Sensex, retreated 0.7 per cent to 16,300.42, according to preliminary closing prices at 3.30pm in Mumbai. The gauge slumped 3.2 per cent last week, its steepest loss since the five days ended December 16. Production at factories, utilities and mines unexpectedly declined 3.5 per cent from a year earlier, the government said Friday, compared with a 4.1 per cent increase in February. The median of 32 estimates in a Bloomberg News survey was for a 1.7 per cent gain.