Sergio Aguero gave Roberto Mancini’s men a half-time lead before Samir Nasri and Yaya Toure made certain and substitutes Mario Balotelli and Adam Johnson completed the rout.
Norwich were outplayed for most of the game but did claim a consolation 10 minutes from time with a Steve Morison header.
It was a quick return to winning ways for City after last week’s draw at Liverpool and took their impressive league goalscoring tally to 48 after 14 games.
Mancini made eight changes after their midweek Carling Cup quarter-final win at Arsenal but defender Kolo Toure was surprisingly retained ahead of Joleon Lescott.
Nasri, making his third successive start, also kept his place and responded with an influential display, linking well with Aguero and David Silva throughout.
Edin Dzeko, the third City player to stay in the side after Tuesday, had the game’s first opportunity after two minutes when he dragged a shot across goal from distance.
Wales striker Morison had a chance for Norwich early on when the ball bounced kindly for him on the left but he also missed the target.
He failed to make the most of another opening when he raced clear in the 10th minute as Joe Hart came out to force him wide and Kolo Toure got back to clear.
After that scare, City began to step up the pressure with Dzeko getting in another attempt but having to settle for a corner.
Aguero, who had earlier shot at Ruddy, then spurned a glorious chance when he volleyed over from seven yards from a Nasri cut-back.
Dzeko again had Norwich back-tracking when he nutmegged Russell Martin 40 yards out and charged to the edge of the box but Marc Tierney deflected his shot wide.
City’s opener eventually came in the 32nd minute after Anthony Pilkington failed to cut out another Richards break.
Micah Richards closed in on goal and then pulled back for Aguero, who showed nimble footwork to turn past Leon Barnett and poke the ball through a crowded goal area to score his 13th of the season from six yards.
Aguero could have had a second moments later after Yaya Toure won the ball in midfield and set up Nasri to cross but the former Atletico Madrid man again fired over.
Despite that home superiority, Norwich had a chance to equalise two minutes into the second half as Elliott Bennett chased a long ball.
Bennett had chance to shoot but opted to go round the advancing Hart and took the ball too far wide, from where he could only shoot over.
Norwich paid the price for that miss as the impressive Nasri doubled the home side’s advantage after 51 minutes, although it is doubtful the Frenchman meant it.
Nasri got lucky when he floated a free-kick into the box from the left and the Norwich defence left it to run through to Ruddy.
The goalkeeper was slow to react and was unable to claw it out as it bounced in front of him and crept in at the far post.
City immediately threatened a third as Silva cut in from the right but Ruddy made a fine double to keep out his shot and Aguero’s attempt on the rebound.
The resulting corner found its way to Gareth Barry but the England midfielder could not keep his shot down.
City’s third came in the 68th minute as Nasri came short to play a one-two with Silva at a corner and the Spaniard fed Yaya Toure on the edge of the box.
The midfielder nonchalantly allowed the ball to come across his body and curled in a low shot at the far post.
Nasri was removed moments later as Johnson was sent on and Mancini also decided to withdraw Aguero soon after. Balotelli, who was sent off against Liverpool, took his place.
Victory was all but a formality but City, having conceded in their previous six league games, were again unable to keep a clean sheet as Norwich replied.
Morison was the man on target, rising at the back post to plant a firm header past Hart from a corner.
The hosts restored a three-goal advantage two minutes from time as Yaya Toure played in Johnson, who turned to square for Balotelli in front of goal.
Ruddy palmed out the Italian’s initial effort but it looped up into the air and the striker calmly nudged it over the line with his shoulder.
There was still more to come and City added a more emphatic gloss to the scoreline in injury time as Johnson placed a low shot past Ruddy.