traveling from Canada to India and I have 17 hours layover in Shanghai Pudong Airport

Hi

I'm traveling from Canada to India and I have 17 hours layover in Shanghai Pudong Airport. .can I go out and come back ? do I need transit visa for this ?
If yes then how to apply as they mentioned "Mailed applications are not accepted by most of Chinese embassies or consulates in overseas."
Please help

Regards,
Harshita