Hi,
SP is higher than ACP.
ACP is basically a DSP/ASP ranked Officer who is junior to SP or DCP. Superintendent of Police is a higher post. SP is equivalent to Deputy Commissioner(DC) of Police in the commissionerate system. While the SP post is always occupied by an IPS officer, ACP can also be held by a State Police Service (SPS) officer.
ACP stands for Assistant Commissioner of Police while SP stands for Superintendent of Police. ACP is the name of the post while SP is the substantial rank.
Let me clear one thing that in big cities like Mumbai, etc there is Commissionerate System means the city is headed by a CP (Commissioner of Police), assisted by DCP (Deputy Commissioner of Police), ADCP (Additional Deputy Commissioner of Police), ACP (Assistant Commissioner of Police) then SHO and other ranks.
Officers not below the rank of DIG are posted as CP.
Sr. Superintendent of Police (SSPs) rank officers are posted as DCP.
Superintendent of Police rank officers is posted as ADCP.
Deputy Superintendent of Police rank officers is posted as ACP.
Hope this helps.
Good luck.
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