As the haze swept over the island this week, it left unsold burgers, empty tables and at least one cancelled quiz night in its wake. The restaurant industry, dependant on the great outdoors and a general feeling of well-being for its custom, is buckling under the weight of the haze.

At least one restaurant will be forced to shut down completely for a day - not just because of worsening patronage, but worsening health.

"We're all sick. We're dropping like flies," Bjorn Shen, owner and head chef at Artichoke Cafe & Bar told The Business Times yesterday, his voice rubbed raw from a bout of fever.

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While Mr Shen's restaurant has bookings all through this weekend, Artichoke will close next Tuesday so that its team of 12 can regroup. Mr Shen reckoned that this one-day shutdown will cost him thousands, which will not be covered by insurance.

"It's just something that that I have to bear," he said.

While dining volumes have slumped in general, outfits that feature an al fresco element are seeing a pronounced impact.

At Nosh, a restaurant and bar at Rochester Park, the weekly quiz night - which usually fills its open dining area - had to be cancelled for the first time on Wednesday night, costing the outlet the custom of some 80-100 people that the quiz usually draws. "In terms of revenue, of course it's affected us," said Ravin Bajwa, Nosh's manager.

"We even contemplated closing the restaurant down for the next few days. When I think of the staff, forcing them to get on the MRT and come all the way down, I feel bad. But you can't just shut down for four or five days and not make any money."

Even as restaurants struggle to operate with the constraints of staff and space, patrons are beginning to stay away. Caffe B at Marina Bay Sands, which has a restaurant and a bar that functions as an al fresco area, is bracing itself for a 15 per cent drop in customer traffic this weekend if the air quality worsens.

"We have . . . had quite a few advance bookings cancelled. Moreover, due to the haze, we have had to limit the bar seating to our indoor area. This has put us in the position of unfortunately having to turn away a few customers due to our indoor area being filled to its capacity," said its operations manager, Michael J Kumar.

"Conversely, our restaurant business, which is located within The Shoppes, has improved quite a fair bit as we encourage our customers to stay indoors."

Elsewhere in the industry, The Senso Group - which owns Spizza, La Nonna and La Villa - is in the rare position of having a mix of indoor, outdoor and delivery operations, which appear to have mitigated the effects of the haze.

"The lunch crowd is still strong, and based on our reservations for the past few days, there is still a visible dinner crowd in our outlets. But this may change as the haze worsens," said its PR and marketing manager, Anastasia Goh.

While McDonald's, Pizza Hut and KFC suspended deliveries until further notice as at yesterday, Spizza is continuing to deliver. The deliverymen are being given priority for the group's stock of N95 masks, Ms Goh said.

As restaurants focus grimly on getting past this weekend, others - such as Artichoke's Mr Shen who will close his restaurant's doors for a day next week - are already scanning the horizon with some trepidation as air quality declines.

"I don't even know if you're going to get well if you stay at home," Mr Shen said, with a rueful laugh.