Option 1:Route 40A from Avadi busstand and ask for albert theatre. This is bus route.
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Option 2: Take EMU to Chennai Central Cross over to Chennai Parktown and another emu to Chennai Egmore or a bus route no 17D to egmore station and its walkable from there.
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OPtion...
more... 3: Take EMU to Chennai Beach and the another EMU from there to Chennai Egmore and walkable distance from there.The EMU takes some time from PER to MSB.
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My personal opinion take option 2.