If you're being harassed on Instagram by a pushy family member or cat-crazy friend, you'll be happy to know that you can block them from seeing your account. You can't "delete" followers in the traditional way, but you can block them from viewing your profile. You can also choose to make your account private to prevent new unwanted followers.
Steps
Part 1 of 2: Block followers

Step #1. Tap the Instagram app to open Instagram
If you're using a computer, go to Instagram's website.
You'll need to log in with your Instagram account information if you haven't already done so

Step 2. Go to your profile page
To do this, tap or click on a person's icon. If you are using a smartphone, you can find this icon in the bottom right corner of the screen.
On a computer, you can find this icon in the top right corner of the screen

Step 3. Tap or click on the "Followers" option
You should be able to find this option to the right of your profile picture.

Step 4. View your list of followers
You can't force a follower to unfollow your profile, but you can block them from following or viewing your account.

Step 5. Click or tap on the follower you want to remove
The follower's profile will now open, where you can block him or her.

Step 6. Tap the button which consists of three dots to open the menu
You'll find this button in the top-right corner of the screen (or to the right of the follower's name if you're using a computer).
If you're using Android, the dots are in a vertical line instead of a horizontal line

Step 7. Click or tap on the "Block User" option
On Instagram's website, this option is called "Block this user". After choosing this option, Instagram will ask you to confirm your choice.

Step 8. Click or tap "Yes, I'm sure"
The selected user will now be blocked and he or she will no longer be able to see your messages.
- The user you blocked will still be able to see your comments on other users' photos and they will still be able to search for your account. However, the user cannot view your account.
- You can view a list of your blocked users at any time by going to the Settings menu and selecting the "Blocked Users" tab.

Step 9. Repeat this process for each follower you want to block
If you want to avoid getting unwanted followers from now on, you can make your account private. As a result, users will have to send you a follow request that you must approve before someone can view your account.
Part 2 of 2: Making your account private

Step 1. Open the Instagram app on your smartphone
By making your account private, anyone who wants to follow you will have to send you a follow request. You are the only person who can approve that follow request. This gives you more control over who has access to your Instagram account.
- Making your account private will also prevent users from accessing your comments and likes, with the only exception being public posts (your name will appear alongside other likes, but your account will still be protected).
- You cannot change your account privacy settings on a computer.

Step 2. Open your profile if you haven't already opened it
To do that, tap the person-shaped icon in the bottom right corner of your phone's screen.
You can also do this on a tablet

Step 3. Open your account settings menu
Do this by tapping the gear icon (iOS) or the three dots (Android) in the top right corner of the screen.

Step 4. Scroll down to the "Account" group
This is a series of account options tabs. The option "Private account" can be found at the bottom of this group.

Step 5. Swipe the slider next to the "Private Account" option to enable it
The gray slider should now turn blue to indicate that your account is now private.
- If you want to turn this option off again, just swipe the slider back and tap "Ok" in the pop-up window.
- Note that enabling this option will not affect your current followers. If you want to block some of your current followers or block them all, you will have to do this manually.
Tips
- Blocked users will not be able to see photos of you in their "Photos you like" tab.
- You'll still be able to see the blocked user's likes and comments on your photos, but you can manually delete them if you want.