What counts as a "specific effect" of the Guards and Wards spell if the Dispel Magic spell is cast on it?

Question

The description of the Guards and Wards spell says:

Guards and wards creates the following effects within the warded area.

Corridors. Fog fills all the warded corridors, making them heavily obscured. In addition, at each intersection or branching passage offering a choice of direction, there is a 50 percent chance that a creature other than you will believe it is going in the opposite direction from the one it chooses.

Doors. All doors in the warded area are magically locked, as if sealed by an arcane lock spell. In addition, you can cover up to ten doors with an illusion (equivalent to the illusory object function of the minor illusion spell) to make them appear as plain sections of wall.

Stairs. Webs fill all stairs in the warded area from top to bottom, as the web spell. These strands regrow in 10 minutes if they are burned or torn away while guards and wards lasts.

Other Spell Effect. You can place your choice of one of the following magical effects within the warded area of the stronghold.

• Place dancing lights in four corridors. You can designate a simple program that the lights repeat as long as guards and wards lasts.
• Place magic mouth in two locations.
• Place stinking cloud in two locations. The vapors appear in the places you designate; they return within 10 minutes if dispersed by wind while guards and wards lasts.
• Place a constant gust of wind in one corridor or room.
• Place a suggestion in one location. You select an area of up to 5 feet square, and any creature that enters or passes through the area receives the suggestion mentally.

It also says:

The whole warded area radiates magic. A dispel magic cast on a specific effect, if successful, removes only that effect.

I'm having trouble parsing the "specific effect" here:

• Are all the corridors a part of the same effect? Or is one effect just one square? Or just one corridor?
• Similarly, are the fog and intersection confusion the same effect?
• Similarly, if I have two "magic mouths" as per the "Other spell effects"-clause, is each a unique effect?

What exactly is this spell trying to say?

Answer 1

The text is unclear.

The two major explanations that immediately come to mind are 'all things of the same category are the same effect' and 'each individual instance is its own effect'. So if you successfully cast Dispel Magic on a warded door, under the first explanation, it would dispel the effect on all warded doors. If you cast Dispel Magic on a warded door under the second explanation, it would dispel the effect for that door.

Fog would count as single effect under both explanations - other paragraphs use multiple phrasing 'webs', 'each', etc, but the corridors section just says 'fog', singular.

Under the second explanation, which honestly I am leaning towards as being most supported by the text, each magic mouth, each dancing lights, each individual stairway's worth of web, each arcane locked door etc, would be its own effect that would need to be dispelled separately. This would in effect be treating Guards and Wards as a set of spells rather than a single effect.

In fact, the only reason to include that sentence "A dispel magic cast on a specific effect, if successful, removes only that effect." would be to make clear that you can't remove the entirety of Guards and Wards with a single cast of dispel magic. The unclear part is to the degree to which you need multiple castings of Dispel to remove it.

As it is unclear, at least in my reading, the DM will need to decide how exactly this spell is adjudicated at their table.

The only part that seems clear is that a single casting of Dispel Magic is not enough to remove the entire Guards and Wards spell effect, and it will need, at minimum, several castings (total number depending on presence of stairs, doors, corridors, magic mouths, stinking clouds, gust of wind, etc)