The phrase "severe bottleneck" refers to a situation where there is a significant obstruction or blockage that restricts the flow or progress of something. It implies that there is a major problem causing a slowdown or hindrance. Full definition
Of course, this kind of argument could be applied to any energy technology that requires rapid ramping up, as all face severe bottlenecks of one sort or another. (smh.com.au)
Last year's division of Conrail by Norfolk Southern and CSX, while causing fewer problems, nonetheless generated severe bottlenecks, some of which have yet to be resolved. (railwaygazette.com)
Significant events in the last 100 years, such as wars and economic depressions contribute to reducing the genetic diversity of breeds by producing severe bottleneck conditions such as political or geographical isolation, at times having reduced the effective breeding stock of particular breeds to only a few dogs. (animals-universe.info)