Since most of the research projects are funded by public agencies, data from NGS sequencing projects, and not only those, should be publicly available after the publication of the results. Each sequencing experiment contains a vast amount of not only sequences but also other information ready to be discovered.
Often the research group responsible for data sequencing and analysis extracts only a small percentage of the information contained in the sequencing data. That is one more reason to make deposited raw data data accessible to the public. Opening data to other scientific groups enables the extraction of more information on other topics and therefore increases the value of data sets and the productiveness of the invested public money.
Two public NGS data repositories were created, one at EBI, the European Nucleotide Archive (ENA) and the other at NCBI, the Sequence Read Archive (SRA) where producers of NGS sequencing data of any kind can upload their raw sequencing data and describe the nature of their data in details.
Unfortunately, due to budget constraints, NCBI decided to discontinue this service and will close the database in different steps. However, data producers are encouraged to submit their data to other existing NCBI databases such as GEO, dbSNP, WGS, TSA and GenBank, that of course will not have the same level of data integrity. Read more on SRA.