The Visa Bulletin for July shows that there will be slowdowns or "retrogressions (visa unavailability) in several employment-based immigrant visa categories for individuals from India and Vietnam for example, before the end of the government's fiscal year. The government fiscal year ends on September 30th.
Department of State’s Visa Bulletin for July 2019 includes the following notes:
It has been necessary to retrogress the Mexico E4 and SR final action dates for July to keep visa issuances within the annual numerical limits. With the start of the new fiscal year in October, the final action dates will be returned to the latest dates established during FY-2019.
India and Vietnam will each reach their per-country annual limit for some Employment-Based (EB) categories. This has resulted in the Vietnam date being held and has required the imposition of a July final action date for India for certain categories. For August, both countries will become subject to the same final action date that applies to China-mainland born employment fifth preference (EB-5) applicants and will remain so for the remainder of the fiscal year. Such action will only be temporary, with the EB-5 date for each advancing for October, the first month of fiscal year 2020, as follows:
U.S. Citizenship and Immigration Services (USCIS) has also announced that the agency will follow the “Final Action Dates” chart for the month for accepting I-485 Adjustment of Status applications for these applicants.
For further information on Visa Retrogression, please see this link for the current Visa Bulletin and USCIS explanation here.