Instargram was working in China before the Umbrella Revolution in Hong Kong. During Umbrella Revolution, pictures and News about the Revolution was shared across the social media platform. At that time, it was the only social media platform at that time that was not blocked by the Great Firewall of China. The platform was working for a while and it was unnoticed by the authorities before the Umbrella Revolution.
Even if the Umbrella Revolution did not take place, I believe the authorities would still discover instargram and block it. Many popular website and social media platforms are blocked in China, Some of them include: Google, Facebook, Twitter, Pinterest, Reddit, Youtube and a host of others.
Many things are banned in China. China regulates their Internet usage frequently. Therefore, they have their own apps to use. WeChat is very popular and it allows them to do a multitude of things including posting photos, communicating by messaging and calling as well as making payments. Therefore, WeChat does the same as Instagram. China may be wanting for their Chinesecompany who made WeChat, Tencent, to grow and it won’t be able to grow if they allow their citizens to use their competitor’s product.
So, Instagram may be banned for this reason or that they can’t regulate a product that isn’t owned by China. Facebook is also regulated and is only recently allowed to be used by the Chinese. However, it is limited to certain uses.