The city of Bnei Braq has been hit by the CoronaVirus particularly hard and the Haredi community there, and elsewhere, is reeling from it. It is not just from events like the funeral yesterday of a Peleg-associated rabbi that has hundreds in attendance not keeping any of the social distancing rules, but the minyanim and mikvas and general population density of Bnei Braq makes it troublesome. I don't know what reports are exaggerated and what is real, but they are talking about many people there having caught the virus and it spreading like wildfire. Only now are the community leaders there finally taking notice and changing their tune as far as behavioral instructions.

To that end, Rav Chaim Kanievsky just issued a psak a short while ago that they hope will be more effective in making people stop and take notice.

Rav Kanievsky paskened, currently specifically for Bnei Braq and not in general, that people should daven alone at home and not in any shul. People should NOT make private minyanim. It is pikuach nefesh.

Rav Chaim Kanievsky adds that anyone not davening at home but in a minyan has the status of a rodef and if you are aware of such a minyan or person you must report him to the authorities, even with the knowledge that this might lead to him being arrested or slapped with a large fine. If you are aware of someone who is meant to be in quarantine but is not following the quarantine rules, you are allowed to shame him publicly over this.

Rav Kanievsky also added that this is not just for davening, but people should also learn Torah at home and not in shuls, even alone in shuls and batei medrash.
source: Behadrei, Kikar, among others

Many people find interesting and creative ways around this in other cities in which this has already been in practice, such as balcony or porch minyanim with people each on their own porch davening together with someone central they can all hear leading the services. It is cute, but the rabbonim did not say to find a way around it. They said daven at home. As innovative as such solutions might be, and seemingly safe, they create an atmosphere of looking for ways around the rules, and even if this or that person is careful to do it while following the guidelines strictly, maybe other people will take example without being as careful. Additionally, I myself have seen such minyanim that seem to be ok, but then other people join in below in the center in the parking lot between the buildings and porches, and invariably those people often are not keeping the guidelines carefully. Stop trying to outwit the system. Just daven at home, as the rabbonim say to. Right now be machmir on pikuach nefesh.