ACR

ACR is one of the new rules imposed in the new chart rules.

Background
In Spring 2017, Ed Sheeran had every single from his 3rd studio album Divide in the top 20, with only one other song in the top 10. To deal with this issue, the OCC issued new chart rules. Alongside the 3 song rule, which means an artist can only have 3 lead singles in the chart (which will be the 3 most popular), ACR is a more complex rule so we have a page describing it.

Why a Song Will Go On ACR
If a song has spent 10 or more weeks in the top 100, and has had 3 weeks of decreasing sales, it will go on ACR.

What Happens
A song will lose around 30% of its streaming and sales when the chart is compiled, hence knocking it down the chart. This can be detrimental to a song, e.g. "The Box" by Roddy Ricch fell from 3 to 25, however it may not have much affect, as seen with WeekNd's Blinding Lights, which fell from 2 to 5.

Why Do This?
The OCC states that it hopes to showcase new hits, music and talent from in and out of the UK. It also boosts the number of new hits by over 10%, with certain hits including Hurtin' Me and Don't Need Love hitting the top 10 that would previously have probably not. Despite this, some people still don't like it, and believe it to be an unfair representation of the charts.