IS 24 hour transit visa allowed for Pakistani passport holders travelling through Ghuanzhou Airport

Yes, Pakistani citizens are definitely and undeniably allowed to use 24 hour visa free transit via Guangzhou airport. You should just take care that your entire transit time is shorter than 24 hours. If your transit time is relatively short, for example up to 8 hours, you will not apply for a temporary entry permit, but you will stay that time airside. When staying airside, you are not a subject of immigration or customs control, but you will just walk from one to the other gate. Also, you do not need to fill out any forms and to perform any formality. You are advised to use correct terminology because this is not 24 hour transit visa, but 24 hour visa free transit, so there is no a visa of any kind at all. Have a nice journey.

Thankyou for clarifying. I just wanted to confirm that are Pakistani passport holders allowed to go outside the airport if they have a layover of 10 hours at Guangzhou Airport ?

Well, exiting outside the airport is totally different thing. If you want to exit the first thing you will do upon landing in Guangzhou is to approach 24/144 hour visa free transit counter where you will apply for a temporary entry permit. This application is free of any charge and here you will present your flight tickets. Now, it will be up to airport officials whether you will be granted a permit to exit the airport or not. You have to be aware that the issuing a temporary entry permit is not a passenger's right, but more like a bonus that can be granted, but also it does not have to be. This is usually granted to those with long layovers, overnight layovers, disabled passengers, passengers with small children and similar. In any case, you can apply for one and if rejected, there are no consequences... You will just return to the transit area. In any case, I wish you the best of luck.