Method 1: Unsubscribe at the time you receive a notification from a website-

Chrome offers a simple single click opt-out and if you right click when you receive a notification, it will show an option to disable notifications from that domain, as shown below. Just click on that link to unsubscribe. Here is an example:-

Method 2: Unsubscribe from receiving notification from a website without a notification-

Here are step by step instructions to unsubscribe from Chrome Push Notifications.

Open a new browser tab and type chrome://settings/content and you will see the below pop up.

 [Note: You can reach this by settings -> advanced -> privacy settings -> click content settings]

1.A pop up with content settings will appear. Go to Notifications section. Click Manage Exceptions

[Note: You can reach this by settings -> advanced -> privacy settings -> click content settings]

2. A pop up with content settings will appear. Go to Notifications section. Click Manage Exceptions

3. This will list all the URL from where you have subscribed to notifications. You can click on the URL of the site you want to unsubscribe. You can allow or deny or completely remove a website.

For Firefox, follow the steps outlined here (summarized Below)

Go to the Firefox menu and select Options.

Select the Content panel and click the Choose… button under Notifications.

Select the site.

Click Remove Site.

For Mobile Browser

If you are trying to unsubscribe from Chrome Mobile browser, follow the following steps.

Open the Chrome browser, then go to settings by clicking the menu on the top right.

Go to Site Settings

Next Click on Notifications. Here you will see a list of websites to whom you have granted permission to display notifications. Select the site you want to unsubscribe, and then click Clear and Reset.