Environmental activists and officials have raised alarms over the rapidly decreasing water levels of the Caspian Sea, emphasizing the urgent need for collective action among the bordering nations.

But now a much better northern route was available, via Batum to Baku on the Caspian, and thence, across that inland sea, to Krasnovodsk, Askabad, and Tashkent. At this period the number of German and ...