If the blockage is deeper in the pipe connecting the gully to the main sewer:
Kitchen gullies get blocked for three main reasons:
How do you know the issue is specifically with the gully and not just your sink? Look for these tell-tale signs: kitchen gully drain blocked
The best cure is prevention. Start these habits today:
Kitchen gullies are particularly susceptible to clogs because they handle a high volume of organic and greasy waste. What is a Gully? | Catalyst Services UK If the blockage is deeper in the pipe
A blocked kitchen gully is a nuisance, but it is rarely a disaster. With a pair of gloves and some patience, you can save yourself a $200 plumber bill.
You have done all the steps, but the water still isn't moving. Or worse—when you run the sink, water bubbles up out of the ground. What is a Gully
Kitchen gullies are the "first line of defense" for your drainage system, meaning they catch all the debris that escapes your sink. Common culprits include:
Don’t reach for the phone to call a plumber just yet. In many cases, you can fix this yourself with a pair of rubber gloves and a little elbow grease. Here is everything you need to know.
Don’t Panic! How to Fix a Blocked Kitchen Gully Drain (Step-by-Step)