diff --git a/Lumi/Cert_299996-303819_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt b/Lumi/Cert_299996-303819_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
new file mode 100644
index 0000000000000000000000000000000000000000..936299a286232ede0e08ef73962962cb6b6d2e26
--- /dev/null
+++ b/Lumi/Cert_299996-303819_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
@@ -0,0 +1 @@
+{"299996": [[21, 1143], [1173, 1271]], "300018": [[1, 281]], "300027": [[1, 112]], "300043": [[1, 342]], "300088": [[1, 310]], "303819": [[2, 21], [36, 653]]}
\ No newline at end of file
diff --git a/Lumi/Cert_306896-307082_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt b/Lumi/Cert_306896-307082_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
new file mode 100644
index 0000000000000000000000000000000000000000..545bfaa6b28521c90a58a3fb329a66c49aa2d45d
--- /dev/null
+++ b/Lumi/Cert_306896-307082_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
@@ -0,0 +1 @@
+{"306926": [[67, 88]], "306929": [[1, 247]], "306936": [[60, 1448], [1450, 1652]], "307014": [[78, 1245]], "307015": [[1, 397]], "307016": [[1, 317]], "307017": [[1, 761]], "307042": [[62, 573], [575, 575], [577, 577]], "307044": [[1, 86]], "307045": [[1, 17], [19, 50]], "307047": [[1, 526]], "307048": [[1, 191]], "307049": [[1, 24]], "307050": [[1, 320]], "307051": [[1, 513]], "307052": [[1, 24]], "307053": [[1, 57]], "307054": [[1, 62]], "307055": [[1, 878]], "307062": [[1, 795]], "307063": [[1, 230]], "307073": [[67, 388], [845, 938]], "307076": [[1, 620], [622, 1669]], "307082": [[82, 1384]]}
\ No newline at end of file
diff --git a/Lumi/Cert_318939-319488_13TeV_PromptReco_SpecialCollisions18_JSON_LOWPU.txt b/Lumi/Cert_318939-319488_13TeV_PromptReco_SpecialCollisions18_JSON_LOWPU.txt
new file mode 100644
index 0000000000000000000000000000000000000000..28e73b2c662a2a8a353bebed90fd6ed8a6d10e49
--- /dev/null
+++ b/Lumi/Cert_318939-319488_13TeV_PromptReco_SpecialCollisions18_JSON_LOWPU.txt
@@ -0,0 +1 @@
+{"318939": [[29, 140]], "318945": [[1, 2], [8, 208]], "318953": [[1, 1163]], "319460": [[10, 62]], "319462": [[4, 18]], "319463": [[4, 13]], "319464": [[1, 114]], "319466": [[9, 35]], "319467": [[1, 242]], "319468": [[2, 1101], [1104, 1795]], "319472": [[1, 225]], "319488": [[9, 1089]]}
\ No newline at end of file
diff --git a/Lumi/README.md b/Lumi/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..ac13b0372b99fa6957a206079bdded4ce8ace624
--- /dev/null
+++ b/Lumi/README.md
@@ -0,0 +1,32 @@
+# Lumi mask files (a.k.a. Golden JSON files)
+
+## For LowPU data
+
+### 2018
+
+Copied from
+
+```bash
+/afs/cern.ch/cms/CAF/CMSCOMM/COMM_DQM/certification/Collisions18/13TeV/PromptReco/Cert_318939-319488_13TeV_PromptReco_SpecialCollisions18_JSON_LOWPU.txt
+```
+
+### 2017C
+
+Copied from
+
+```
+/afs/cern.ch/cms/CAF/CMSCOMM/COMM_DQM/certification/Collisions17/13TeV/ReReco/Cert_299996-303819_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
+```
+
+### 2017H
+
+Copied from
+
+```bash
+/afs/cern.ch/cms/CAF/CMSCOMM/COMM_DQM/certification/Collisions17/13TeV/ReReco/Cert_306896-307082_13TeV_EOY2017ReReco_Collisions17_JSON_LowPU.txt
+```
+
+### 2016
+
+Currently, the 2016 lowPU data is not availible.
+