The Argentinian seemed to fall out of favour at the Etihad last season under Pep Guardiola, with the Catalan preferring Gabriel Jesus to the club legend Aguero.
The Blues will try to sign a striker this summer to replace Diego Costa, who has been told he is not in Antonio Conte's plans for next season.
Chelsea are keen on the likes of Alvaro Morata, Pierre-Emerick Aubameyang and Andrea Belotti and a surprise name now being linked with a move to Stamford Bridge is Aguero.
India planning missile with eye on all of China: US report
India said it was asked to intervene by Bhutan and that the construction had implications on its own security. Both India and Pakistan control portions of Kashmir, though both nations stake a claim to the entire region.
Antonio Conte is searching for a new striker after telling Spain global Diego Costa earlier in the summer that he was free to leave the club.
Sky sources say "it will be very hard for Chelsea to sign Aguero" but that their interest is real. We are a team that aspires to win every competition we compete in. "It has never been in doubt".
Chelsea have been linked with making a shock move for Manchester City striker Sergio Aguero today.
"Having Sergio Aguero as part of the squad is an absolute must".
Aguero has been a superb signing for City since arriving from Atletico Madrid in 2011 and he still has three years left on his deal so the Citizens are under no pressure to cash-in.
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